Well there are a lot of other forces. For one, I take pride in building great things. I code for work, and when on vacation I build side projects, because I enjoy it.

Another is if I see a team trying to get something done, and they need my expertise, I enjoy the act of helping them.

Those employees are really only in it for the money will do the bare minimum. I'd say tops half of employees have this mentality. The rest care (often too much) about what we do.