I once got let go from a company, and then, 2 weeks later, they offered to re-hire me. They acted like they were doing me a favor, boasting that they'd even pay me the same salary. I declined, as I was planning on quitting anyway. Then, a few days later they sent me a threatening letter, claiming I stole company proprietary data, and they were gonna report the situation to the district attorney if I didn't contact them. I didn't respond and never heard from them again. I heard from former colleagues that no one knew the admin passwords for their critical systems except me. That's true. I told management, over and over, that the whole sysadmin operation revolved around me, which was doomed to fail. That's actually why I was planning on quitting. Oh yeah, when they let me go, I offered to stay on for a short time to cascade to whoever was gonna replace me. They declined and rushed me out the door.