Eclipse

Small, picky or doubtful breaches of the law should NOT be called in soccer.  This is referred to as "trifling."  Older law books contained the following guidance: 

“The Laws of the Game are intended to provide that games should be played with as little interference as possible, and in this view it is the duty of the referees to penalize only deliberate breaches of the Law.  Constant whistling for trifling and doubtful breaches produces bad feeling and loss of temper on the part of the players and spoils the pleasure of spectators.”  -- Law 5, International Board Decision 8

For example, if a player lifts his or her foot a ¼” on a throw-in, is it a rule violation?  Yes.  Is it trifling?  Also, yes, and therefore, generally it is not called.  This, of course, causes more demands for another eye exam for the referee.

This statement has been omitted from recent editions of the law book because it is universally understood (well, maybe not by Americans, but the rest of the world understands.) 

Trifling also is skill and age related.  In professional games, you will see players holding each other all the time and we’re sure that referee hasn't seen his opthamologist.  As long as the holding doesn’t interfere with their ability to play the ball, professionals generally expect some holding and know how to play through it.  However, in a U19 boy’s game, uncalled holding can escalate into a fistfight.  

So the next time you see a small foul and the referee doesn't call it, ask yourself -- "Could that incident be considered a minor or trifling breach of the laws?"  If so, please congratulate the referee for his or her sound judgement!