Howard Stern, Mos Def and Sandra Bullock were all on David Letterman last night and posed outside the studios.

You know, some people don’t understand the impact your hair can have on you, but look at Sandra Bullock.  She looks beautiful in all the pics, but having her hair down (with the same outfit on) makes a huge difference.  See, men don’t understand how we can be in a bad mood if our hair isn’t working for us.

Does having a bad hair day affect your day?

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Photos:  WENN.com