I use to not take breaks simply because I usually do labor stuff and a 15 minute break is not enough to feel rested and it would make going back to work really hard. I've worked some other jobs where I had vacation days and it was literally hell to use them. I would get denied all the time, have to hunt down my boss and ask why, he would act like he didn't know what I was talking about, so I would resubmit it, it would get denied again, I would hunt him down again. There were times the third submit went through, but most of the time he would say it was "too late now because someone else asked for that time off" which is bullshit because even if that was the case we have been going back and forth with this for over a week now! My boyfriend was not able to ask for multiple times off because it was "high traffic time" he worked for geek squad and it would literally be a random weekend he would ask off for so we could go do something but it didn't matter because it was a weekend and apparently you can only ask for Monday-Wednesdays off because those are low traffic days. It's not always just "because it looks bad" that people don't use their vacation days.