Winning Chips

It's important to remember that in poker you want to win chips, not hands.  Just because a hand is favored to win, doesn't mean it's a good value to play; for example, when playing 4-way, a hand like A2 may well be the best hand out, but you may still want to fold it from under the gun.  The problem is you are likely to win a small pot if you win, since if an ace comes anyone with no ace will fold.  If the pot is big, it's probably because someone has a better ace and you'll lose.  Hands like this can only win small pots or lose big pots, so even though you think you probably have the best hand, it's still bad to play.

Winning a lot small hands may not be a good play if you are setting yourself up to occasionally lose very big ones.  This is why you don't just always bluff all-in with your whole stack, but it applies to all your plays.

The only exception to this is when you're calling all-in; calling all-in is actually a very simple situation in poker.  You know there's no further action so you don't have to think about future scare cards, will people fold, implied odds, etc.  You just have to think about whether your chance to win is good enough for the pot odds being offered.