In life, every decision we make will be somehow based on what we feel we can get back from it.
Is the gym worth it for me?
What will I get out of it?
Will it make me happier?
Even situations from when we were all very young. I remember having to choose my friends at school- should I hang around with the naughty kids because they're cool, got away with a lot more and didn't really do much work? Or should I hang around with the clever kids that would potentially help me with my exams and to be a better person?