First let me say that I've been reading through all of the posts on this site and there is an amazing amount of information in here. What a great a forum! Thanks to everyone who has contributed.

I play NL ring games and I am wondering what you guys think about something:

When you hold KK and someone goes all in ahead of you or there is a preflop raising war, should you always go all-in?

I know KK is a really great hand, but the last 5 times I have had KK and pushed all-in preflop, I have lost.

Twice to AA.
Once to 86s - got flush.
Once to AK - caught wheel straight.
Once to AQs - caught ace *and* queen.

Are these beats just a run of bad luck?

I am losing confidence in KK.