[pzhon]

It is possible to find places to fold KK preflop correctly, sometimes even without a specific read on a player. That there are also times to call all-in with KK, and that you may come out ahead by calling all pushes with KK, does not mean you can't do even better.

In very low level games, you can't be confident that you are up against AA without a specific read, since so many players overvalue hands like TT or AK. Despite the generally passive play, a push will often be a weaker hand.

At higher levels, the general level of aggression is high enough that players will 4-bet all-in with a wide enough range that folding KK is incorrect.

There are some games between these two at which typical players are passive and predictable enough that you can comfortably fold KK to a push from an unknown player when one of the players involved is in early position.

One common misconception is that you have to be very sure that you are up against AA in order to fold. In fact, AA is more of a favorite over KK than KK is a favorite over {QQ-KK, AK}, so if the push was a big overbet, even a 50% chance that you are up against AA instead of {QQ-KK, AK} means you should fold.

Another common misconception is that the small probability someone has AA before you see the action tells you much about the probability you are up against AA in the rare scenario that someone represents a huge amount of strength. Most of the time when you have KK, your opponents do not have AA, but they also usually either fold to your raise or call. When you see someone 4-bet all-in over your reraise, or push over your 4-bet, you have to ask how often your opponents would do that with less than KK.