can anybody think of a selfless good deed??

That's easy. Being made happy by making someone else happy is selfless. There is no loss of virtue from feeling good because you've helped someone else. When you do a work of charity or compassion, you do so because the other person needs your help, charity, compassion, or good deeds. You don't do it to feel better afterwards. If you feel good about yourself afterwards, it is irrelevant as to determining the selflessness of the act. But, if you want to be even more cold hearted about it. People will do good deeds for people because they believe they should, not for some emotional high. Anything you do which puts you out of your way is a selfless good deed. For example, my sister came up to visit us for a week because she needed a break from her living situation. I love my sister and there were things I enjoyed about the visit. However, I gave her a place to stay because she needed one and I sacrificed my own privacy. The selfish thing would have been to keep my privacy for a week and stay outside her troubles. The selfless thing is to invite her into my home and give her a brief sanctuary. If, at some point in the week, my sister did something nice or we had pleasant conversation, that is irrelevant.