i agree, but in my opinion, the 'right thing' becomes blurred when there's no positive incentive. holding the door or not, i'm not really doing a bad deed either way.
the right thing, a nice thing, or something a little less than that ... do it because you want to, not just for a momentary "thank you". That's the kind of attitude, I believe, leads to a lethargic and apathetic spirit.