teething vs PMS

I think that these are the same, kind of.
Like, when a chick is in a bad mood, people assume "oh, she must be pms-ing" and when a young child is grumpy we say "oh, he/she must be teething."
I wonder if the babies are ever thinking "i'm not teething! i'm just having a bad day, ok? it's not always teeth!" and getting annoyed by the accusation... just a thought...