Pot control.

What was your plan preflop if an ace came? It should of been not to put in more than x% of your stack.. or a certain # of bets.

Its okay to check/call the flop to reevaluate. Remember KK is just one pair.. pick a better spot to commit that much of your stack.

Don't feel bad about how you played this.. its annoying for someone with Asmall to play like a donkey and outflop you. There was a really good post about how to play KK with an A on the flop in the recent past. Anyone know the link to it?