a bad day in general (from the belief that the appearance of one's hair is connected to how well the day goes)
I think you must be having a bad hair day.
A bad hair day is also a day when everything is going bad. It has nothing to do with how one's hair really is, it's just that everything is going wrong. The term "bad hair day" derives from how psycho one feels because everything is going all wrong on a particular day!!
Grabs handsful of hair and tugs in indesperation, "Arrrrrgh!! I'm having such a bad hair day!!"
A day in which, despite normal styling efforts, one's hair looks bad, wrong or strange.
"Honey, why are you so late, and what's going on with your head?" "I'm just having a bad hair day."
Michael Bolton is a Permanent Bad Hair Day
When you sperm in someones hair and then use it as hair gel.
That guy just gave her a bad hair day!
The act where in the male receives fellatio by a female wearing a baseball hat and at the point of no return, releases himself into said baseball hat, then putting it back on her head and twisting it around Jorge Posada style.
Shes been in the shower for an hour cause he gave her the ol bad hair day.