Of course, you only ever do things because there’s something in it for you,
No, sometimes you do things because you care about other people and want to help them. That you also probably feel better about yourself than you would if you did shitty things all day doesn’t mean that feeling is the only and single motivation.
That would be an extremely reductive definition that doesn’t really tell us much about how caring for others is actually experienced and how it manifests in the world. How would this for example explain sacrificing yourself to save another person, if the very core of caring is to create positive emotions in yourself? Dying is a pretty negative thing to experience and there will be no more positive emotions for you after that. I guess this idea that caring is in its essence transactional feels profound to people because we’re so ingrained with capitalist ideology… but it’s a lot more complex and multifaceted than that.