none

i resign.

Are you one of those players, OP?

Probably they are wrestling with the new Android app ;p

actually, I hang on to the bitter end. Looking for a stalemate or draw.

They're within their rights to resign whenever they want.  Deal with it.

I know why! Because their mighty plan of fools mate fails when you make the ''wrong'' move..

lots of reasons. got a phone call had to take. got a call from downstairs had to deal with it. realized your rating and decided to not play anymore. as LIMark said, was looking for an opening. Just looked at the time and realized they were late for something, and had to run. There's absoutely nothing wrong with resignation ever. Its the people who don't resign, and bug their opponent to resign, or who make repeated harrassing draw offers, or who stop moving and abandon the game without resigining, those are the problems. 

if i have a pawn or two down i might resign.....

I must say when higher rated players abort games with me I can't help but feel annoyed. It's pretty demeaning, and it doesn't take much effort to change your online settings to whatever ratings you want to play.

I never resign even when i should but i hate quitting

I've seen some players like that, one resigned dozens of games after the first move, and these were online, 3-day-per-move games, so the "I need to rush off and tend to something important" reason doesn't fit.