More tales of Bad GMing in this thread.
coconut!!!!
Real life
Cashier: "Sorry we're out of big macs, would you like a McChicken instead?"
Lobolusk: "Sure, that's alrCOCONUT!"
Even better...
Cashier: "Would you like nuts on your sundae?"
Lobolusk: "No, thanks, just coconut."
On topic:
The worst GM I ever played with was ...
Me
Mary Sue/Marty Stu DMPCs ... check
Taking away player agency (while not directly, I allowed another player to, so) ... check
And other more egregious sins.
Fortunately, I've grown up quite a bit since the bad old days. :)