Christina Hendricks -- My Boobs Are NOT a Conversation Piece!!!!

One day after she wore a top that shoved her boobs into her chin ... "Mad Men" actress Christina Hendricks SHUT US DOWN when we asked a TOTALLY FAIR question about 'em.

Hendricks was out in L.A. Tuesday night when we asked if she ever gets tired about people talking about her gals ... when she refused to answer and walked away from our camera.

Of course, Christina hasn't always been so shy about her chest ... and if you're not a blind person, you can see the proof below.