Personally I think that if you are over 18 then you shouldn't have to be asked to clean up after yourself. You also shouldn't assume that other people should have to clean up after you, that you are somehow too good to take the initiative and join in without being "asked politely". I'm not your mom. I shouldn't have to ask.
You may not agree. That's your perogative, but realize that everyone is judged on their own behaviour and you may not come out so good in the judging. Suck it up and be a better person. And the next time you see your mom, you might want to ask her why she didn't teach you right.