THEY COULD BOND OVER SO MUCH! Carrie would be like "My life sucks, I fell in love with a ginger terrorist!" and Deb would be like, "Oh yeah? I fell in love with a ginger serial killer... who also happens to be my brother. Man, these Showtime writers are weird." But then they discover their mutual love of ass-kicking, being badasses, fall in love w/ each other and go on to have the best show ever, basically.

Also Carrie could probably refer Deb to a really good therapist, one that doesn't condone incest.