Personally, KK and QQ I will re-raise preflop all the time. On the flop, I will make a decision based on texture and what my opponent has been communicating to me through their bets and overall play so far (tight, loose, c-better, etc.).
A major leak of mine that I recently identified is getting "married to my cards." AA, KK, QQ are nice hands, but in the end, they are just a pair. Always put some thought into your play before making a move, especially post-flop. They are not invincible. If you're beat, you'll probably lose money, but the goal is to lose the least amount possible.
Pot
odds and
equity always play a factor for me too. Low limit online players love shoving their stack on the flop when they hit something, which is usually a huge over bet, hoping that someone with a drawing hand or an inferior hand will be dumb enough to call them. Sometimes they hit light, others they hit hard.
For example, if I'm holding AA and I re-raise preflop and villain calls that re-raise (assuming he was the original raiser) I take note of that. If the flop comes Q-J-10 rainbow and he shoves, there are tons of things he could have. QQ, JJ, 10-10. QJ, J-10, even 8-9 or AK. All of which would have my AA crushed. SO, I ask myself: is it worth committing almost my entire stack to win a small pot just because I have AA? I don't care if villain is
bluffing or not...it's not a good $$ deal.
Let's say you fold and the villain was bluffing. Now, the player may begin to think he/she can push you around. The next time you hit hard against him, use that to your advantage and stack them!
As far as AK goes, a huge leak a lot of players have is over-playing this hand. It looks nice, even suited, but it needs to improve to have anything. In the end, it's just an A-high hand. Re-raising preflop my be okay in later positions, and I'd definitely open raise this in any position, but post-flop, if you don't improve and don't have position, dump it. If you're in position and the villain(s) check to you, a 2/3 or 3/4 c-bet might be okay, depending on the situation.
Sorry for the long post...