AK is really hard to play on the flop - especially when you NOT hit. But you still have 6 outs to make top pair with top kicker and are a huge favorite against AQ or a lower ace. And when you are known as tight player your opponents maybe put you on QQ+. :wink:
Particularly, most of the time a board appears as you mentioned I give up the hand. I continue to bluff only when I have a lot of information from the player and "I suspect" that he is a bluffer or does not have a pair in his hand.