We are selfish

Everyone is selfish. Selfish in a sense to make themselves feel good.

We are selfish for goods. We work hard for it or we steal it. Either way, these stuff make us feel good.

We are selfish for good feelings. We help people because that gives us a sense of emotion that will make us feel good. Whether it's a sense of accomplishment, sense of savior, or a sense that people are looking up to or like you. We are good in nature, and that's just because we are selfish and being good makes you feel good.

We are selfish to make ourselves feel good. Our action is determined by our value of how much good/happiness can we get from each action.

We go to school, because a sense of being able to have a good future makes you feel good (this is hope), or it can be because of selfishness for knowledge, or a sense of accomplishment etc. But sometimes we lose a sense of happiness in an action (school). If you can't get any kind of happiness out of it as a motivation, that's when you start failing, though if a sense of failure makes you lose more happiness, you may actually want to work hard yourself just so that you don't lose more happiness. But if you don't value a sense of failure as making yourself losing more happiness, that's when you give up.