Earlier quoted context omitted.
Wrote my post before I saw this one. This is in line with what I was thinking, an act of altruism to make yourself feel good is not pure altruism. I also agree that it is about the actions more than what you gain by doing so. Charity is a good example of how altruism helps yourself, I donate to charity every now and then and of course it makes me feel good about donating, thus the act has an emotional gain for me.
I actually struggle with this idea myself. I consider myself a good person, and I enjoy helping others. Sometimes with a fair bit of cost to myself. But I don't consider it "altruistic". I help them because I want to help them and enjoy having done so, and not out of some innate sense of ethics or of what needs to be done. I think people doing altruistic things do enjoy them, but they don't do them because they enjoy…
For example, a restaurant owner might serve food for free for homeless people for increasing their own reputation and social wellbeing, vs the owner who does it entirely out of the goodness of their hearts. The net result is the same, so why worry so much about the motivation behind it? I'd say they're both equally good people, in this example.
Being able to be generous and therefore altruistic is also a decent signal to the rest of your group you're fit and healthy.