Dogtrousers
Kilometre nibbler
"I'm good" is also used to mean "No, thank you". As in "Would you like another piece of cake?" "I'm good" (which means "No, thank you, I have had sufficient cake".)The person who first replied "I'm GOOD" when someone asked how they were has a lot to answer for then.
I suppose if you answered "I'm bad" that would mean, "Yes, an extra large slice please"