I thought it was really funny when a, IIRC, Oilers fan got so mad at Ducks fans for overhyping Sam Steel on the trade boards (or polls, maybe) that they changed their username to SamSteelFan4Ever or something like that.
Back then, usernames could only be changed like once every 6 months. And the user was... let's say it wasn't the first or last time they may have let their temper get the best of them, so I think they were banned for an extended period on that username. So all in all, they had that username for what felt like years.
Maybe not the best username, but top tier level of cutting off their nose to spite their face.