I can only speak for myself and not anyone else. Personally, I never resign, it's too humiliating for me and I personally feel it's like saying I'm a quitter although I know no one would think less of me if I did resign an obviously lost game. Also, there are two annoying times when people do resign: When you're one or two moves to checkmate and the fortunately less common time of resignation which is resigning while in fact winning. There's even a web page about resigning when winning:
http://timkr.home.xs4all.nl/chess2/resigntxt.htm
Another reason I don't resign is the objective of chess is to checkmate the opponent's king, although I do respect everyone who does resign.
If it's personally right for you to resign a lost game, do so, but if it's personally wrong for you to resign, then don't. And have fun no matter what happens, good game 

fortune favours the brave