Most of this isn't possible on forums. Besides; I've tried leaving. I physically can't. I feel actual withdrawal effects when I stay off for some time.
Take reddit pills. Cures addiction fast. Side-effects include fedoras and being a euphoric gentleman.
There are quite a few sites (like Kinja, who do comments on Kotaku) that don't let you delete accounts. Thankfully, you can usually get your user name changed and edit the posts so it appears to be somebody else's account.