I learned Ruby so I could stop making so many typos when writing MUD areas.
From 2002 to ~2015 I played a Merc-derived MUD called AVATAR. A rare area building contest was hosted by the Immortal staff, and after writing a tiny newbie area filled with sleepy ents and one angry warlock, I was offered the privilege of writing areas regularly.
AVATAR's codebase hails all the way from 1990's DikuMUD, and its area file format grew harder to manually read and write with each new feature added to its syntax. AvVerify was my first ever Ruby program—I learned as I went—built to parse area files and report possible errors.
MUD areas contain the entirety of the game's lore, and with enough contributors it sort of becomes a shared fanfiction of itself. I spent countless hours researching in-game lore to find interesting story lines to pick up, and concoct mysteries that I hoped other writers would investigate and embellish on their own.
I should emphasize that area building was one of the most rewarding creative pursuits of my youth (and young adulthood). In retrospect, I wish I hadn't stopped, but a combination of d̻e̠͉͔p̟̟̰ͅr̘̦e̩̫̗̟̜s̗͍s̻̝i̞͖o͉̻̪̩n͚̰ ̞͈̻̬͔a̝͖͉̳̻̰͈n̦̝̘͓̞d s̤̙o̻̘̱m̞̦e͉ l̩̯͎̼̦̣o̶̶͍̬o̯̙̙̱͚̻̙ͫ̆ͦ͋m̧͍̻͜i̧͓̩̲͚̹͕̺͘n̴͇͔̱̩͉̠͝ͅg̝̦͇̦͟͝ͅ i̛͏̨̛̯͚̥̺̟̪̫̙̗s̷̢̛̛̰͇̻͖͈͉̙̮͍͙̪͓̥̤͔̳͝sͦ̍͑̄̅̌͏͇̭̜͔̺̹̖ͅų̣̘̜̳̲̘̘̣̣̰̦͘̕ȩ̢̱͙͉̤̮̬̹͖s̢͏̢͔̹̯͙̣̺̹̩̥̥͕̠̙̠̦̬̠ kept me from keeping up contact with my peers. 😶