Of course, you should take a couple weeks off from work under normal circumstances, but when things go sour at your job and the writing is on the wall to leave, you really should take a trip right before you quit. I remember, during my last job, when I was passed up for not a promotion, but a lateral move. I didn't get it, not because I wasn't qualified, but because part of the snowball effect was the work area and subgroup I was in. They were such rotten, incompetent cretins that if I'd had made the lateral move, they would have collapsed as a group. In other words, I was needed as a continued babysitter, but in reality, that was the passive-aggressive way of telling me I didn't belong there, despite all I did for the company.
He never bothered telling me the news that I didn't get the job, but he never bothered to explain why, so I just said I was quitting, and I did it without incident. I planned the vacation perfectly so that by the time he made the announcement, I was already at the airport. I didn't want to be around for any backlash, drama or distractions. The workplace was about to get a lot worse with my departure, as he had pandered to the interests of idiots and the weakest links he failed to fire, while chasing off workhorses like me. My way of telling him "fuck you" was taking a trip before the last week of work, and making sure I had no PTO left after that, as I couldn't cash out any unused hours upon resignation.