There is a difference between normal, everyday irritability and chronic, episodic irritability that causes you to fly into a rage and oh, I don't know, scream profanities and physically assault your husband as I have done. Irritability that goes above and beyond mere annoyance is not exactly an ordinary emotion.

I think everything involved in bipolar can be considered an ordinary emotion - except it's been amplified by a million and causes great suffering to those who experience it. So I don't think it's as simple as psychobabble pathologizing everything.