What do you mean with changing psychology? I see that all your "successful" projects involve making someone else happier/helping them. Was it about noticing your impact on them?
I changed many beliefs and thought patterns that were causing me suffering. This included ideas I had about myself and society and how things "should" work.
Yes, making an impact on others is very rewarding.
Making things for myself is nice, of course, in fact the pleasure of making something that I myself really like can be greater than the pleasure of making something for someone else. When I say "pleasure" I mean something like a sensation in the body, the stomach.
But things can be greatly rewarding without involving much pleasure. This can often involve a sensation of warmth in the heart.