If we go out on one date, do not expect me to say Hello! every day.
I really don't like the Nao! Nao! Nao! attitude. One or two dates does not make a relationship. I can date other people, you can date other people. I would expect you to date other people, that way you can see they are far less awesome then me. I don't think exclusivity is something that should be assumed. I think it is something that should be stated "Hey, I dont want to see other people!" or something to that affect. I don't believe it is possible to have a long term relationship without having a short term one first.
Now at some point in the future, if things go well, and the relationship kicks up a bit, then yes, I'll say hello daily, but really, come on. Just because I bought you dinner doesn't mean I have to say hello to you every day.