There are three situations from what I've seen, one is toxic workplaces where PTO is closely tracked and people who use it are punished (socially or otherwise). That happens more often in unlimited PTO places, but absolutely happens in places with traditional PTO plans too. Second you have the more common situation where without a use-it-or-lose-it resource people end up taking less PTO than they would normally, this happens naturally A LOT. Third are people who have never worked somewhere with unlimited PTO who are justifying to themselves and others why it's bad :)