Earlier quoted context omitted.
Same here. Unless it's your own activity, you shouldn't work more than what's written on your contract. If you work more, you get abused and low-balled by salary negotiations
There's a fine line of course. Just like you don't want to be the guy working 20+ hours of free labor every week, you also don't want to be the guy who is out the door at 5:00:01 every evening and not a second before or after. I think most people in most jobs will have something come up where they do a little extra, if only to help out a team member or something.
If I need to help a team member, I skip lunch to pitch in.