In Dickens' novel A Christmas Carol, Mr. Scrooge bemoans that his employee expects a day off calling a day off "a poor excuse...to pick a man's pockets." That's an attitude which, alas, remains common inside today's work environments. Not as blatantly stated, of course, but present nonetheless.
While most companies give lip service to the idea that vacations are good for their employees' work/life balance, many bosses implicitly discourage employees from taking vacations or otherwise try to ruin them, using the following tactics.
1. Only granting vacations when it's convenient for management.
I've heard credible stories of bosses who won't give employees vacation days to attend a child's wedding (or a parent's funeral). Similarly, there are people who have paid for expensive cruises, only to be told that they can't take the time off, even though they were promised those dates before making the reservations.
2. Assigning an expiry date to earned vacation days.
Bosses who pressure employees not take vacations frequently set up a "use it or lose it" system where unused vacation days vanish at the end of the fiscal year. This reinforces the notion that vacation days aren't something you've earned (in which case they'd accrue) but instead something the boss "giveth and taketh away."
3. Pressuring employees to remain "on-call" during vacation.
Because the wireless connectivity is universally available except in the remotest of vacations spots, bosses (and coworkers who are supposed to cover for you) rightly assume that you can be reached. If something comes up that requires your overcommitted "sub" do substantial, you're likely to be called and asked to handle it.
4. Shaming employees for actually taking a vacation.
The boss will subtly (and not so subtly) rib you with remarks like "For the next two weeks, Chris here will be slacking off..." and "So, how did you enjoy your *long* vacation?" The implication is clear: taking vacation is disloyal to the team and putting an unfair burden on them to do your work for you.
5. Demanding extra work before vacation.
Vacation is supposed to be Paid Time Off (PTO) which should mean "time when you're being paid for not working." However, if (as is often the case) you're expected ahead of time to do a substantial amount of the work you'd normally be doing while you're gone, you're just shifting your work hours. It's not really Paid Time Off.
6. Allowing a "mountain of work" to accumulate during vacation.
Similarly, if, upon returning, you're expected to answer all your emails and handle anything that came up while you were gone, it's not PTO; it's just shifting your work hours. Same thing if somebody else is supposed to "cover" your work (atop their own full workload) while you're gone. You're expected to reciprocate; again, that's just shifting work around rather than PTO.
7. When bosses fail to take vacations themselves.
Bosses set the tone for their organizations and become touchstones for acceptable behaviors and attitudes (aka corporate culture). Bosses who insist upon being fully connected to the office while "on vacation," or don't take vacation days at all, are communicating clearly to everyone that real vacations (i.e. disconnected and without shifting work) are an unreasonable expectation.
8. Unlimited Vacation Time aka Unlimited Paid Time Off
UPTO sounds like a great perk, but if you're in a company with a culture that discourages employees from taking vacation, UPTO transforms what's supposed to be an earned benefit that you deserve into something that your boss bequeaths as a reward. Under UPTO, only the boss's pets are likely to actually get as much PTO as they would have earned under the old system.
Ruining employees' vacations (which is the end result of the ploys above) is monumentally stupid because a real vacation--one without interruption or extra work before and after--actually does "reboot" your emotional system, making you a better and more effective employee. The Scrooge attitude is thus "penny-wise and pound-foolish" as would have said in that era.