Please explain “My Bad” – free thumbs

Okay….call me old or whatever, but really, what’s with this “my bad” thing?

For every ying, there’s a yang…is there a “my good”?

I don’t even want to discuss the grammatical aspect of the phrase….it just hurts my head.

So….thoughts…..is there a “my good”? And if so, what is it?

Darryl~

edited to clarify subject line