The pressure depends on the level of play and the fairness of both sides. It also depends on the level of game, competitive or recreational. Most of all referees are cursed at by the players, coaches, and fans. It starts with the coaches. If the coach uses poor sportsmanship then the players pick it up.
Coaches are usually more openly critical than the players.
Fans can also be quit critic al. Most referees just ignore the problem and try to be calm, but when the game gets out of control the referees have good excuse. Referees usually start refereeing because they want to stay in the game, a way of supporting the sport, when parents want to stay in the sport with there kids, and people needing for referees. Coaches, players, and referees are always trying to their best. Usually the referee should say almost nothing, and when he or she does, with politeness and a smile.