My technique is worth gold, you should be paying me for just postng this... I did this a year ago...
1. find a shrink (psychiatrist) and say you are depressed, having thoughts of violence, suicide, etc... do something if you have to like attempted suicide. (I did not, but I will not tell you what I did)
2. ask shrink to give you sick note for 2 weeks, then go back to office for 1 week or so, then go back to shrink say you cannot take the work sress, thoughts of depression coming back. need more time off, this time a month... you get the idea. you should get paid from STD or LTD insurance while you are sick. If you are good at this and can get up to 2 years worth of pay from LTD without having to work a single day. I only got 1.5 months.
3. Do not go partying during your sick days. keep this cycle for like 3 months, the company will get sick of you and offer your package to leave. Find a lawyer to represent you and squeeze the most out of the company especially now getting fired will might make your "condition" even worse, get doctor's letter with it. if you are working for a big company, they will not want to look bad, will probably give you a sweet deal.
I got 8 month package from a company I worked for 5 years using this technique...
please don't hate me for this..