If he'd really been doing that job for 20+ years, I'm surprised he didnt go off on people earlier.

There's a lot of people who have serious entitlement issues. The story that I've been hearing is that the passenger stood up before they announced it was safe to do so. The flight attendant asked the passenger to sit down, passenger refused and either opened the overhead and pulled out their bag and it either fell on the attendant's head or the passenger intentionally hit him...along with using some colorful language to insult the flight attendant.

You can only take so much abuse from the public before you snap.

I wonder how long that guy had been fantasizing about jumping out of the plane with a beer using the emergency exit slide... If you're going to quit your flight attendant job, that's an impressive way to quit.