Eh, I agree to a degree. Not that you should act like someone is below you, but act like you'll never get intimate with them. A lot of people jump right into the "ZOMG, I WANT TO FUCK HIM/HER" and then go about playing a game to make it happen. Any time you act hasty like that, you're going to make mistakes and in this case BIG mistakes that you'll most likely regret or hurt your ego.
So, it's better to just be friendly with everyone and after awhile certain people will click with you that will make you feel comfortable about taking on that next step.