You could possibly take him somewhere public where you think that other people might be doing what irritates you and say to him, in quite confidential tones, 'doesn't it irritate you when people do that sort of thing?' - if he says no, then you could say something like, 'oh well, I suppose it's just the way I was brought up/raised, it drives me up the wall/round the bend' etc. etc. If he goes on to say that he is guilty of it, then you could say something like 'oh well, maybe a little - but never as bad as that!' - thus making it clear that you don't like it, but also that he isn't the one you're 'immediately' irritated by...
just an idea - but Alexandra's probably right about the honesty thing <img src="/images/graemlins/smile.gif" alt="" />
best wishes - Jane