How does "whole other bag" happen to mean the "completely different one"? I'm curious about the origin of this expression.
"Whole other bag" means "a whole different matter/situation/problem/issue." It originated from the expression, "whole other bag of tricks." It's an American idiomatic expression that does not make sense literally, but can applied to a variety of situations. You can also use similar expressions like, "whole 'nother matter," or "whole other thing." Ex: I thought that my experience as a model would help me in acting. But I was wrong! Acting is a whole other bag. Ex: It's one thing to babysit your friends' or siblings' kids. But having your own kids is a whole 'nother matter!