well you got to think of things that you need in life, not want in life ;)
i am with you on the luxury part, but think of others before you think of yourself. lets say your on your way to buy this fancy car that you don't really need but you just would like to have one, and this poor guy passes by you counting his coins barely able to buy a properly meal you'd just have this sting in your heart that would make you very annoyed.
if I can't afford it, I don't get it. Simple, not complex. If I needed it to survive, I'd be dead by now.