You should respect the difficult job that referees have and recognize that the referee, according to the FIFA Laws of the Game, is the ultimate authority on the field. Whether a coach, spectator, player or parent, you should not vocally dispute a referee call (or even call out for an explanation) during the game. The coach may speak privately with an adult referee at halftime or after the game to seek an explanation. Youth referees should NOT be approached at half time or after the game to discuss calls. If you have a question, it may be directed to the youth referee through the Referee Assignor or Director of Referees.At no point in time, in the history or future of soccer, will a referee's decision be reversed.  You must consider this when deciding if you want to "argue" with the referee about a call or seek "clarification" as to why a call was made.  In the end, you still may not agree with the call, but you will at least know why the referee made the call.Many of our referees are young.  They are some of the best kids around and have played soccer and respect adults.  Do not take advantage of that respect by "bullying" them after they have made a call.  It teaches your players bad sportsmanship and may get you removed from the game and/or coaching.Many of our referees are also coaches.  This means they have been subjected to "bad calls" from other referees.  Understand that the referee cannot see everything and what they do see, they may see differently than you.  This is a part of the game and you must teach your players to adapt and overcome any obstacles to perceive are out there.