Can't is a four-letter-word

So Braxton in what happens to be infinite wisdom of a two year old has decided that throwing temper tantrums is a thing of the past. (ok, not totally, but I am witnessing a change.) He has now decided that when I tell him its time to do something he doesn't want to, he should inform me that he is incapable. This is how our conversations go:
Me: Braxton its time for bed (or substitute anything you can imagine a two-year old doesn't want to do i.e. pick up toys, eat veggies - you get the picture)
B-rox: I can't mom.
Me: Yes, Braxton, you can
B-rox: No, I can't
Me: (trying to keep my cool at this point, or keep from laughing. You choose which) Braxton, its time for bed lets go.
B-rox: (also visibly frustrated, and continuing to chow down on his cheerios) MOM, I said I can't!!!!!!!!!!
THis is the point in the conversation when I pick him up and carry him to the bathroom. He doesn't much care for it, but by the time we sing "itsy bitsy" its all good.
Two year olds....