The problem with 15/10 games.

The problem with 15/10 games is that after a while I get totally fed up with waiting for the other guy to move, that when it's finally my turn I often ironically make more hasty and stupid moves than in short games. I just don't want to contribute to all the god damn waiting. 

I wish I could get better at them but I guess I'm too impatient most of the times. I think the most I can spend on a move are 2-3 minutes tops. I like being able to play without being affected by time but ironically I get affected in another way in these long games. 

I even think that if I make computer analysis that I make more mistakes in longer games at times. 

Who else feels the same?