I do the exact same thing, full ring game, no-limit, $200 or $500 max buy-in game.

I always, 100% of the time play my A+ game with my first buy-in. I ALWAYS build up my first buy-in to a similiar 2-5 times my buy-in.

Then... I start to feel invincible, make to many over-calls, and try to pull of moves that have negative EV.

I can't explain it. Recently... I have been playing with the sole function of doubling up and walking away. If it's a profitable table oh well... if I'm the best player... oh well. I have figured out how I work... and I'm not going to fight against the tide any longer.

Now... sometimes I will go back to the very same table 1/2 an hour later... but once I doulbe my stack... i get up.