Make decisions based on what's right for you.
Ask yourself: "What do I want?"
All things for me to keep in mind.
It's not a question of being a nice guy vs. being an asshole. It's taking care of yourself (and you can't take care of others if you're a shambles). It's not even putting yourself first; it's putting yourself on an even footing with everyone else. You're just as good as they are. Your needs are just as valid as theirs.
There's nothing noble about being stepped on.