Ever since I can remember - and I'm 35 - my mom has given the mailman a christmas present... tin of cookies, bottle or brandy, etc. that type of thing. Just something - varied every year. He probably would have preferred a $20 spot but dunno.
My wife and I do not. Yep, I'm a cheap bastard I guess. Do you tip your fast food drive thru person too? They put up with more shit, for way less pay... now, the better service angle I can buy.