Since the mid-2000s, most companies expect everybody to be pseudo on-call at all times without any additional compensation thanks to cell phones and the internet making everybody reachable at any time. Your boss calling you after work, on the weekends, or while you're on vacation to talk about work is normal and they expect you to be accessible at all hours of the day. At shittier jobs like retail, you can even expect to be called on your days off and asked to come in if somebody doesn't show up or something, even in the middle of the day, and if you aren't available or "flexible" you can expect it to negatively impact your job.

At my first job for a small business, I didn't take a vacation (not even a single day) in 10 years because the boss didn't give us vacation days and instead said that anybody could take days off at anytime and he'd make the schedule work, but we were always understaffed and he'd make you feel guilty for taking days off. That's closer to the norm these days in the US than the 6 weeks of vacation time that is the norm in Europe. Large companies are required to give you 2 weeks plus a handful of sick days, and that's it.