I think it's very important to have a game plan on what you want to do BEFORE even heading out into the woods. If you plan on taking the first animal that provides a shot, you shouldn't feel slighted if a monster walks out of the brush while you are dressing out the spike.
However, if you plan on taking a trophy, you also shouldn't feel bad if you pass on three or four smaller deer and don't get a shot at the big boy.
Either way, you've accomplished the mission you've set out to do. Don't worry about the "what ifs". You'll drive yourself crazy. If you have a plan and follow it, you will eliminate any hesitation or worries when crunch time comes.

ALWAYS CALL YOUR SHOT.