In "Homer Goes to College," Homer gleefully sets his high school diploma aflame, while singing, "I am so smart, I am so smart, S-M-R-T, I mean S-M-A-R-T!" Behind him his living room is going up in flames.
The now legendary "S-M-R-T" line was actually not in the script and was a genuine error by voice actor Dan Castellaneta. However, the error was so much in Homer's character that they chose to include it in the finished product.
Peoplenowchant either "S-M-R-T" or "I am so smart, S-M-R-T", particularly when they're feeling stupid, celebratory, or both.
An acronym for Sex, masturbation, anal, rectal, tits. It's a machine used for self-pleasure. Mass production of the S.M.A.R.T. began in the early 2000s, and still continues today.