I think any time we exhibit surprise that someone emboides traits we do not normally associate with that gender/race/culture, we are in effect demonstrating our bias. Using an example above, if I have a friend who lives in a trailer and I make the comment "She keeps a clean house, even if it is a trailer" I am complimenting my friend, but I am also exhibiting my own bias about mobile homes being somehow lesser when it comes to housing and therefore not worthy of the same care and attention that a house would merit.