There's a lot of good stuff in this thread, so I'm going to just add my two cents to a couple of other people's excellent comments.
JRutledge wroteNo it is not when you understand the rules that are in place.
I agree with this 100%. BY RULE, contact that does not hinder a player from performing normal movements is NOT a foul. That's specifically written in the rules. The patient whistle often (not always, but often) gives you an extra half-second to determine if that little bump gave either player an advantage not intended by rule.
AllPurposeGamer wroteI think there are officials that take the concept too far...and assume since the shooter made a shot, he was not disadvantaged.
I agree with this 100%. For a few years, everybody at camp was talking about not giving the "cheap and-1". And what they were really saying was "don't give and-1s". This led to a lot of officials who think the only reason to call a foul during a try is because the shot missed. But as APG implies, a try can be made much more difficult by a defender's contact and that's a foul -- even if the try is subsequently successful.
rockyroad wrotejust understand that the level of contact needed to impact a play is considerably less in HS games than it is in NCAA games.
I agree with this 100%. If the contact impacts the play, then it's a foul. But a small bump that causes a freshman girl to travel will not even be felt by a college senior on his way to dunking the ball. One is a foul, one is not. A patient whistle allows you to determine which one is NOT the foul.