There is a reason we have the word "selfish" in the English language. The word does not exist for no reason at all. We use it for people who only act in their own self-interest or strictly for their own benefit and enjoyment.
English also has the words "obligation" or "responsibility" which you are totally ignoring, which are frequently used in moral, social, religious contexts.
There are about one thousand things that would "feel good", provide more enjoyment, be more self-interested than going to volunteer to serve inmates in State prisons, distributing humanitarian relief in Gaza, or refusing to tell Nazi interrogators you are hiding a Jewish family in your basement.