A "safe" color is the color that you end up with in a the case of indecision. When you love the red chair but worry where to put it and you get the oatmeal fabric instead.
In looking around my own house I realized that my "safe" color is black. I have caught myself thinking, "Well, I can always move it to another room if it's black."
I have painted furniture black, chosen black lampshades and fabrics, and moved that black chair from room to room.
So tell me, what is your "safe" color?