For me it was last week (Thurs). Retard boss emails me why am i not at work, I tell him my vacation that he APPROVED in our time management software kicked in that Monday, I'll see him on the 31st. Then he says 'oh how did that get approved, I sure didn't do it. I need you in here asap to resolve this list of issues or I'll have let you go'.
IN my case I already had another job lined up to start Jan 7th, and he had pulled almost the exact same vacation shit last year (among a ton of other things) so I rolled in, gave him a nice flowery resignation quitting on the spot, and walked out.
Side note, the letter I gave him, if you spell out the first letter of each sentence, spells out GO FUCK YOURSELF. Hahahaha he'll probably have that thing in my file for the next 20 years and never catch on!