you have to lay it down depending on what type of game you are playing, nl cash game, say you raise and he reraise the board come A, Q, 2, there is a good chance he has the ace if he goes all in, now if he slow play the c-bet then call, and call the river if he slow plays it, don't raise unless you made a straight or trips and no straight possible on the board.. but don't be the agrressive..just my opnion on that subject laying down KK..