"Leaving forever" threads are overly dramatic, immature responses used simply to garner attention. Just leave. And there's no reason to arbitrarily enforce the "forever" part on yourself, because you don't know how you'll feel in 6 months or a year. If you want to keep staying away after that, then by all means keep staying away.

However, I have no objection to doing something obnoxious yet entertaining to get banned. If you're going to do something, at least make it interesting.