Mine is r/breakingbad
I got perma-banned from participating for calling someone an incel in one of the many “SkYler ThE bItCh Is ThE mOsT eViL cHaRaCtEr In ThE hIsToRy Of TeLeViSiOn” threads that pop up on the sub every week, so I unsubscribed.
Before that it was r/realpublicfreakout, which started out as an alternative to r/publicfreakout that actually focused on, er, public freakouts, but quickly descended into some hyper-rightwing “let’s cheer on cops bashing black people” sub during the BLM protests.