Question: is it common for a boss to make you stay late because your teammates are working on something big (that you're not involved in) and they're staying late? Because he touts that it's team unity, but I feel like it's false imprisonment.

That's another management euphanism for extra hours. Don't fall for it.

As with all things management, ignore the words and examine the aims.

Stupidity.

Depends where you live, but generally you only need to work overtime when your contribution is required in order to prevent further damage (e.g. contract penalties, stepping in for a sick coworker, saving someone's life or property, ...)

Now "team spirit" pretty sure doesn't fall under that category, but then, your boss could claim your presence is required because you need to learn about the project to be able to help minimise impact in case something goes wrong in the future.

Just go home already

@netikras this was Wednesday but the ripples are still being felt today.

@hitko that claim would have no basis. The real problem is how the boss reacts to the employee rejecting work. It may be disadvantageous to the employee, even if he has the right to reject.

@electrineer that's my problem I indirectly confronted him and he said it was "team building" and he "jumps at those opportunities". Issue is I told him I don't like staying late unless I have to, told him I didn't want to unless I had to, AND that I enjoyed my job 40-50 hours a week during the interview. And he assured me that it wouldn't be a thing he did. Yet 3 months in: here we are.

Btw, team building usually happens at some bowling/billiards etc. place and a restaurant, paid by the company.