I have been watching, covering (pro and college) and playing sports for about 15 years, and I never felt that refs/umps decided the outcome of the majority of games I've witness.
You can say what about the ref not calling the intentional foul in the Dallas-Denver game? Well, Melo still had to make the three. Now if Melo missed the shot, the Denver fans would have been upset.
What about Rajon Rondo punching Brad Miller and not being called a flagrant foul? Well, Brad Miller has to make the FTs.
What about the ref in the Miami-Ohio State BCS title game who called pass interference in the endzone? The Hurricanes still had a shot to win in OT.
What about the ref in the Denver-San Diego game not calling a fumble by Jay Cutler? Well, the Chargers had a shot to stop the Broncos on fourth down and on the 2-point conversion attempt late in the game.
There are a million reasons why teams win and lose games that don't even have anything to do with the refs when you think about it.
If only the ref would had make this call or not made that call....no what if you did not turn the ball over 15 times, miss nine free-throws, throw three interceptions, walk 8 batters, commit 4 errors and 7 holding penalties?