Reading reviews and comments about the series Game of Thrones so far, at five episodes in, one surprising thing is the number of people who are confusing the characters Robb Stark and Theon Greyjoy. These two are getting mixed up more than any others (although Jon Snow was causing some confusion until he departed for the Wall.)
The actors don’t look much alike so I guess it must be the similar ages and same location that is confusing people. Other characters either clearly look very different or are clearly at a different location. It’s probably because there are so many characters, some of whom haven’t really done anything significant yet, that keeping them straight can be difficult.