Generally, it seems to me that if you find interacting with me to be informative, entertaining, and/or interesting, then the chances are good that you like me; at least to some degree. Maybe not "friends" right away, but definitely moving in that direction.
I recognize there are people out there who get paid to be civil and friendly (i.e. waitresses, bartenders, strippers, etc.) but I'm talking about those people who I "chat up" at random.