I live in Europe and we have at least 21 vacation days per year. My company gave us 25 and 4 sick days per year. The law is a bit grey in this area but usually the company can't reject your PTO request unless they have a very strong reason. However, common sens dictates that you let the company know about your days off as soon as you schedule them. For 1-2 days, unless there is an emergency, a week is enough. For 2-3 weeks at least a month.
Anyway, at the end of January I informed my boss that I will need two days of mid February. I was denied because we are onboarding a new client and the company really needs us there so unless there is an emergency, no days off are allowed until the end of March. This is absurd and I didn't think that the onboarding process will suffer if I'll be away for two days but I didn't want to cause any troubles so I rescheduled my days at the end of March. I spoke with my colleagues and they had the same issue: their days off were declined.
Yesterday morning during a meeting with the client my boss didn't join. I reschedule the meeting and pinged my boss on teams and saw that he's got on out of office message saying that he'll be away for two weeks. I tried to ping another senior colleague of mine but he's also away. Turns out they went skiing together.
I went and had a discussion with HR and then with my boss's boss. They were not informed that we are not allowed to take days off for 3 months and they looked as pissed off as us about his decision to go skiing.
I was already looking for another job anyway. Now I just have a funny story to tell.