I have 2 favorites:

Always the first shot in the round. Standing on the tee, thinking about the round ahead of me and that all the cr*p that took to get me to this point is a very very relaxing feeling. This is what it's all about right? We work so we can play. So lets PLAY!

Then the other is the last iron to the 18th green. This is where I go into my head the most, imagine all the pressure, play all the fun games that you are down 1, need birdie to win, etc...then try to block it all out. "Here he is, about to become the Master's Champion....I think he's got about a 2 iron...oh, he got all of that one...it's in the hole! It's in the Hole!"