A classic example of this was my final play at the 11am tournament I played in last week.
I had an above average chip stack and had 40+ BBs so I was pretty comfortable. I looked down and saw QQ. The UTG called and it was folded around to me in the SB.
I raised it about 3.5x and the UTG re-raised about another 3x. Normally, this would have sent alarm bells going off as the UTG was what I like to call an old codger. Someone who sits there and folds, folds and folds, only raises with premium hands etc.
I called his raise and decided to immediately shove with the rest of my stack if the flop came with under cards. Herein lies my problem. I had made up my mind before I even saw the flop with no recollection of what the preflop play had been.
Of course flop came down J73 with no suitedness or wetness. I shoved and he insta-called with AA. The turn and the river brought me no additional help and I was out of the tournament with another middle of the pack finish.
So, in light of that, I feel that it is time to develop a mental checklist that I go through every hand I play past the flop.