I'm guessing most people don't want to be toast. You might want to be the toast, but that's a different matter entirely. Being the toast is a good thing. Being toast is a bad thing, as you'll find out here.
Basically it means that something is finished. Finito. Whatever. Or that you're doomed. It's basically not good news.
Use in Normal SpeechEdit
When informing someone of doom.
"I'm sorry...I've got bad news...nobody thinks he'll win! Looks like he's toast, sorry!"
When informing that something is finito.
"If you dare make a fool of everyone, yourself included, at my party, my social life will be toast.