Millennials are worried that their bare-minimum style of work habits means their economic value doesn't last too long past the time their ass leaves the office chair. If you're providing real economic value to your employer, taking your due vacation shouldn't be a worry at all. My anecdotal experience: I only get 12 paid vacation days per year but took 2 weeks off July 2016 to take a trip to Europe among the other 2 weeks or so of miscellaneous leave I took so far this year because I bolted down and grinded that last week out to get my project work complete and minimize the impact of my absence. Got paid for the entire 2 weeks and came back to the same environment I left.
And before you get your panties in a wad, of course it's not all, but it's enough of a presence in the millennial working community to garner widespread media attention and academic study.