The Time a PC Tiefling Tried to Murder Us All Out of Spite

I came here before to take the piss at my bumbling mistakes as a DM, but nothing I've experienced pales in comparison to what I experienced back in the D&D 3.5 days with a former roommate in college. This story's short but nonetheless cringeworthy.

I lived with four people at the time, including the DM and the problem player, who I'll call Goober to protect the cartoonishly insecure. The four of us and Goober's girlfriend at the time sat down for the first session, excited for the DM to take his first crack at 3.5 with us. I can't remember what class everyone else was playing, but Goober rolled a tiefling warlock. The session starts with a goal of protecting a coastal town from a band of pirates. The dice gods did not act in Goober's favor the entire night. He was having trouble with nearly every check he made, and he was visibly growing more frustrated.

We sneak onto the boat, inevitably alert the deckhands (pretty sure due to Goober failing a stealth check) and initiate combat with the pirates and their pet tiger for some reason. I'm sure the DM put that in purely to learn balance for combat encounters, and I commend him for trying that, in part because I found that damn tiger hilarious and in hindsight the silver lining of this evening. Goober was still having terrible luck throughout to the point where I for one became pretty uncomfortable.

Combat concludes, with the tiger having messed us up pretty badly. Goober's then proceeds to have his character leap off the ship and throw acid balls at the hull. This was ironically his best roll of the night, and the ship began to sink with us still aboard. He swims to shore and collects the reward from the town's mayor without us. The session ended right after that, and Goober promptly sulked off to his bedroom.

Over the next few years we discovered his behavior to be a prevailing issue with Goober himself that reared its head in other TTRPGs and board games. The worst incident occurred over friction while playing the tactical Game of Thrones board game that resulted in a huge argument between Goober and his girlfriend and days of silent treatments and couch sleeping on his part. We cut ties with him shortly after Goober and his girlfriend broke up, and we became better friends with her than we ever could achieve with him. To this day we all half-jokingly trust no tiefling whatsoever, and I swore off playing the race until years later.

Tl;dr my old roommate effectively acted out a temper tantrum over terrible rolls at the table. This lesson has been taught on this subreddit countless times before, but don't put up with a clashing personality or shitty behavior at your table. It only leads to headaches in and out of the game.