Refereeing is a largely thankless and incredibly difficult task. You will rarely see referees, umpires or officials receive praise for the good things they do, yet pundits, coaches and supporters are all too quick to get on a referees back after any mistake. Referees are asked to make split-second game or even season defining decisions, whilst we have the benefit of countless slow-mo replays, they do not.

For this reason, referees deserve our sympathy in many circumstances. Imagine if in your job, any little mistake you made was under the microscope. Imagine making a tiny error and then having millions of people curse your name and in some cases even receive death threats for one slight misjudgment. This is what referees constantly go through, for a job they don't even have to do, as many referees have their own careers outside of officiating. They are only human, and therefore basic human error is to be expected. However, this list is for those who don't really warrant any sympathy. Referees so bad that they were or are in the wrong profession and deserve all the criticism and ridicule which comes in their direction.

The list includes referees from an array of sports, many whom have officiated at the highest level for a number of years, despite the almost unanimous view that they were or are incompetent. Others were dropped or 'relieved of their services' after a string of unimpressive performances. Here are the top 15 worst referees in sports history:

15 15. Joey Crawford

Joe 'Joey' Crawford has officiated more NBA playoff and finals games than any other active referee, which would suggest that he was one of the best in his field. Yet Crawford is almost universal hated and one of the most disliked referees in any major league sport, which may have something to do with his reputation as one of the strictest referees in the NBA. His most notable controversy came in 2007 following an altercation with Tim Duncan, where Crawford reportedly asked the Spurs star if he wanted a fight. Crawford was fined and suspended by the NBA and has cited it as one of his greatest regrets in life.

14 14. Bennett Salvatore

Bennett Salvatore has been involved in a number of on and off-field incidents over the course of his career. Away from sport, Salvatore used to own a steakhouse and has been in trouble with the police for both ticket fraud and false tax returns. For the former he was sentenced to a year of probation, 150 hours of community service and fined $500, but Dallas Mavericks owner Mark Cuban probably wishes Salvatore had been locked up instead, after a series of bust-ups with the referee. Salvatore made two terrible calls in 2006 and more recently in the 2014 NBA playoffs.

13 13. Joe West

Joe West is one of the oldest and most experienced umpires in MLB. West began working as an umpire in 1976 and has had a number of critics over his expansive career. West's first major incident came in 1983, when he was involved in a pushing incident with Joe Torres, for which he was fined. In 2004, West made such a controversial call that police intervention was required and more recently in 2010 West received widespread criticism for his comments regarding the Red Sox and the Yankees. He attacked the slow pace with which the two teams played, labelling it as a "disgrace to baseball".

12 12. Bryce Lawrence

Bryce Lawarence refereed over 200 first class rugby matches, which would suggest that he was a quality referee, but in his final few years he was far from that. Lawrence was so poor at the 2011 Rugby World Cup that he announced his retirement the following year, citing his own poor performances as one of the defining reasons. In 2009 he was criticized for his performance in a clash between the Lions and South Africa, but it was at the 2011 World Cup that he drew more serious criticism, failing to control a game between Australia and South Africa, he didn't referee another World Cup game.

11 11. Christina Pedersen

Christina Pedersen is a Norwegian female referee who took charge of what is regarded as one of the greatest games in the history of women's soccer. Sadly, it was on this great occasion that Christian Pedersen made her name, for all the wrong reasons. The year was 2012 and the occasion was the 2012 Olympic semi-final between the U.S.A. and Canada, regarded as two of the finest teams in women's soccer. With Canada leading 3-2 and little over 10 minutes on the clock, a series of unusual decisions seemed to go against them.

First a controversial indirect free-kick and then a controversial penalty helped the U.S.A. score a late equalizer and eventually win the game in extra time. Criticism of Pedersen was rife, not least from Canadian player Christine Sinclair, who suggested foul play. Pedersen never took charge of a major tournament again.

10 10. Laurence Cole

Boxing referees are often called into question because they have a greater involvement in the sport than most referees. Boxing referees are often criticized for having too great a presence upon a bout, but equally lambasted for a lack of discipline if they let a fighter get away with too much or fail to stop one boxer from getting seriously hurt. Two boxing referees make this list, and Cole is the first of them. It has been suggested that Cole only holds his position as a ref due to his father's influence in Texas, supported by the fact that Cole very rarely referees anywhere outside of Texas.

Cole's worst performance came in 2014 for the bout between Vasyl Lomachenko and Orlando Salido, in which he failed to spot a number of clinches, low blows and pushes, all of which should be his bread and butter.

9 9. Tim Peel

There is probably no other league is the world where you will find such unanimity as to who is the worst referee in said league as there is with Tim Peel in the NHL. The NHL is, for the most part, an excellently officiated league, but as always, there is an exception to the rule, and that exception is Tim Peel. Despite his series of woeful performances, Peel was somehow selected to referee at the 2014 Sochi Winter Olympics. Peel's most notable incident was probably missing a blatant trip in 2012, but he probably had his worst games over the course of 2013, when some called for him to be dismissed for good.

8 8. Angel Hernandez

Angel Hernandez has been a MLB umpire since 2000, and has taken charge of some of the biggest MLB games, despite being consistently ranked as one of the league's worst umpires, an assertion backed up by the 2006 Sports Illustrated poll of players, which saw Hernandez ranked in the bottom three of officials. He has had notable bust-ups with Terry Francona, Joe Madden and Bob Melvin.

7 7. Jeff Triplette

Jeff Triplette is a retired Army Reserve colonel who has been an NFL official for 19 years. Triplette began officiating in 1996, and his first major incident - which was a bizarre one - came in 1999. Triplette threw a penalty flag which was weighed down by ball bearings and accidentally hit Cleveland Browns player Orlando Brown in the eye. Triplette immediately apologized but Brown never let it go, eventually suing the NFL for the incident. The NFL also had to apologize for Triplette's error when the officials made a hash of the New York Giants 24-17 defeat of the Washington Redskins.

6 6. Joe Cortez

Joe Cortez previously described himself by saying, "I'm firm, but I'm fair." However, a number of boxing fans would disagree. His retirement is 2012 was greeted with jubilation from some sects of the boxing community. A good amateur fighter himself, Cortez became a major boxing referee during the 1980s, taking charge of the likes of Mike Tyson and Roberto Duran's bouts. In 2011, Cortez caused controversy when he took stewardship of the fight between Floyd Mayweather Jr. and Victor Ortiz. Cortez failed to put the fighters in neutral corners and was even pictured looking in the wrong direction as Mayweather caught Ortiz, leading to a barrage of criticism in Cortez's direction.

5 5. Urs Meier

Urs Meier is a retired Swiss referee who had two defining moments to his career which made him hated in two different countries. Meier refereed for a number of years in the Swiss Super League, a league without a great deal of media attention, but whenever the spotlight was on him, controversy was never far away. He first came to the world's attention when he refereed the game between the USA and Iran at the 1998 World Cup, which passed without incident.

It was at Euro 2004 when Meier caused a real stir. There was a petition to FIFA for his dismissal after a poor performance which saw Romania dumped out of the tournament. Weeks later the real controversy began. Meier had been chosen to referee the knockout game between England and Portugal, despite protests in England, given that England had previously beaten Switzerland 3-0 in the competition. Meier put in a horror show, seemingly giving many decisions in Portugal's favor as England lost the game following a controversial disallowed goal in extra time.

4 4. C.B. Bucknor

C.B. Bucknor has been a Major League umpire since 2000, and has been widely regarded as one of the least competent in the game ever since. In a Sports Illustrated poll of 550 active players, Bucknor was named the worst MLB umpire in 2003. When Sports Illustrated repeated the poll three years later in 2006, Bucknor was named the worst in the league once more, and a similar poll by ESPN in 2010 found Bucknor coming out last once more.

Jamaican-born and a former university player himself, one of the primary criticisms of Bucknor is his inconsistent strike zone. Bucknor's only consistency seems to be in consistently being the worst umpire in the league. He has also received criticism for prematurely calling batters out, which has occurred more than once.

3 3. Wayne Elliott (& Replacement Refs)

At the start of the 2012 NFL season a labor dispute between the league and the NFL Referees Association meant that replacement referees had to be called in for the first three weeks of the season. The referees called upon were from various worlds of American Football, including the lower leagues and even some from the Legends Football League (Lingerie Football League at the time), one of whom had been sacked by the LFL for incompetency.

There were large scale complaints about a number of the replacement refs who for the most part looked wholly out of their depth, missing numerous ball spots and making some shocking non-calls. Most notable of all though was Wayne Elliott, who was the official who oversaw the infamous Fail Mary decision at the CenturyLink Field stadium. The dreadful show was the tip of iceberg for replacement referees and two days later the Referees Association reached and agreement with the league.

2 2. Tim Donaghy

It's one thing to be an incompetent referee, it's another to be a crooked one. Former NBA referee Tim Donaghy was the subject of a 2007 FBI investigation regarding point shaving in NBA games. Donaghy had been approached by mob associates to work on the gambling scene. Donaghy was eventually caught and would plead guilty to conspiracy to engage in wire fraud and transmitting wagering information through interstate commerce. Donaghy served 11 months in prison, receiving a lighter sentence in exchange for his cooperation with authorities.

1 1. Byron Moreno

Byron Moreno has been given the kind tag of 'the worst referee ever' by many in the media, particularly those in Italy. The Ecuadorian made his international name at the 2002 World Cup, when he was chosen to officiate the knockout game between South Korea and Italy. In a team featuring the likes of Paolo Maldini, Alessandro Nesta, Fabio Cannavaro, Alessandro Del Piero, Francesco Totti and Christian Vieri, it was no surprise that Italy were one of the tournament favorites, yet they crashed out to South Korea in a game officiated by Byron Moreno and a clash shrouded in controversy.

There are suggestions - including those made by Italian manager Giovanni Trappatoni and forward Francesco Totti - that foul play was involved, and that Moreno had been told to ensure South Korea won the game. Italy had three legitimate goals chalked off, as well as having a questionable penalty given against them and Francesco Totti sent off. Moreno was investigated by Ecuadorian officials and by FIFA, retiring in 2003. He was arrested in 2010 for trying to smuggle heroin through JFK Airport and was handed a 30 month prison sentence.