It’s easy to assume that everybody wants the good for themselves. That’s very rarely the case. What we want is attention, sympathy, empathy, a break, acceptance, stuff like that.
You might say that each of these things are a form of “good.” But each and every one of these things are external, meaning that you cannot get them yourself.
Truly wanting the good for yourself will require you to own your mistakes and take some responsibility. Winging it would not be an option. You would look after yourself like you would look after someone who’s about to have a surgery, making sure everything’s alright. That’s wanting the good for someone.