How to discipline myself at the poker table?

[ATM]

How do i do it i cant seem to discipline myself when it comes to poker meaning telling myself im beat but calling anyway. Had pocket queens the other day and raised and about 5 limpers im in the sb with $10 in a 0.5/0.10 game and raise it to .70 i get one caller from a guy i know is a total idiot flop comes ace high and he moves all in I told myself im beat but somehow ended up calling. You would think that hitting a fold button would be a little simpler.
How do i Stop myself doing this? Has anyone else ever had this problem?