People forget that pocket A's are just a single pair. Lets say you come in for 3x the bb from early position and get 3 callers. There are 13.5 bets in the pot as the flop hits. Flop comes KQ5 rainbow and you have first action. You bet 10 bb's and the button caller raises you to 40 bb's. What do you do? Do you call, fold, push over the top? This is where people screw up with A's. If you push and get called 90% of the time you are chasing 2 outs. The other 10% of the time you are up against a weaker hand that has a chance of beating you. There are times to fold A's post flop and time to push hard.

I'm not a fan of pushing all in preflop, unless you have it limited to 1 other player. You take away your option on the flop to out play your opponent if they flop some sort of a drawing hand. If you bet to take away the odds and they call, make a note on them for chasing without odds. Chance are they have a history of doing this and you wil see them again.