If you have trouble thinking about yourself and prefer to help others instead, why not try to disassociate yourself into the different versions. I like gaming, cooking, anime and building electronics, but I always feel guilty doing these things when I could be helping others out.
What I instead do is, I think about gaming me. I think, that dude would be happy if I can show off the progress I made in Hollow Knight. I think about the cooking me and try to think how to impress that guy with the new sukiyaki recipe I just did. I bet the anime me would love to talk about how comfy Yuru Camp was and how nice the soundtrack was. I get really excited to show electronics me the new battery system for the solar panels I did that I was somehow able to solve cooling issues.
So there you have it. If you can't treat yourself, just split yourself into different people and treat those guys instead.