The worst termination I ever heard of happened to a friend of mine. He had worked long and hard on becoming a good database programmer. He had a job that was not great but okay. Then one day his boss called him in and gave him his three month notice. The job market was crap at the time so this really wore on him. Then, a week before his last day, his boss called him in and told him that they didn't have a permanent position for him but that they could re-hire him and give him another three month notice.
Incredibly, this repeated again. And again. My friend realised that the sole reason they did this was so they could keep him from earning extra entitlements and raises they would otherwise have to give him. But this did not change the fact that he never knew if he would be re-hired at all and he got more and more stressed. And this crap went on for more than a year.
Then one day he ran into an old friend who had also studied database programming. They started chatting and his friend mentioned that they really badly needed another database programmer, did he ever finish his studies? Well, sure he did. He was working as one right now but hated his job. Could he come speak with their boss the next day for a job interview? Damn straight he could. So, he went to the interview and was immediately offered a position, at 50% higher pay. That would be great, he said, he could start next month on the first as he was getting terminated at the end of this month anyway.
So, he went back to his old job. Said nothing. Sure enough, his boss called him in for the usual rehire-and-immediate-termination chat as usual. With barely restrained glee he told the guy, "Nah, not a problem. I start a new job next month so I'm good." His boss blurted out, "What? But -- but we need you!" He responded, "That's fine. I'll stay if you offer me a permanent contract and double my pay." "We can't afford that!" "Too bad, so sad. Byeeeee!" And he walked out LIKE A BOSS.
He started his new job a week later. And for some reason he didn't bother with leaving much documentation behind for whoever they found to replace him.