Changing Things Around

What if one day A decided
To end the alphabet
And 2 got up and walked as far
From 1 as he could get
Then Notes would want to switch is up
And be all flats instead
And Blue would think that he should start
The rainbow and not Red
And Fish could fly and Giraffes would swim
And Joy replaced Regret
I'm sure we'd be confused if A
Was to end the alphabet