Gay
Last Letter threads are the biggest fucking cancer that inexplicably plagues every single forum I've ever been to. Websites with awful "post number reward" systems had dozens of variants. My city council's geocities-looking forum has a goddamn Last Letter thread.
Like, Christ, you're on a website with more content than you could probably read in a couple of decades, yet you're wasting hours of your life on finding a witty follow-up to "two years worth of semen glopping" that starts with the letter "g". Why, who the fuck would would find that fun?
There are tribes in the Arctic Circle that are completely untouched by civilization, who spend a third of their lifetimes with no more than four hours of sunlight a day, all of which are dedicated to hunting and eating raw blubber off bacteria-ridden sea mammals. If you're short on said disgusting whale blubber, there's also a distinct possibility of getting pushed out by your younger, stronger offspring from your home into the freezing tundra to die, so as to save resources. Not even these people could come up with a game as dull and miserable as a Last Letter Thread, let alone keep one up for 350+ pages with constant new participants joining.
There's only one thing worse than that exercise in communal suffering, and that's those stupid-ass Competitive Counting games. Counting threads are where fun goes to die. Presumably after being castrated in a Last Letter Thread. Every one of you is a massive fucking numbskull.