I inherited an old Japanese codebase. Tons of stuff was just single-letter variables. Apparently, this used to be at least somewhat common here. I spent a lot of time just updating code to replace vars with something meaningful (and found bonus bugs due to improper scoping with same var names as a bonus). Didn't have an IDE that would easily do it for me at the time and running something like sed felt too risky.

skibidi = 42