Well, I guess one of the things would be don't walk around everywhere taking tons of pictures. Another most likely would be don't complain about the weather/come prepared for it. Here in the Northwest, we have a lot of rain and very little sun. So you can tell who hasn't grown up here by who complains about the rain/wears shorts and a tank top during spring. Springs tend to be very wet here.
Also, don't be afraid to ask where the best place to eat is from someone. That'll give away that you're not from the town, but you can get a good meal out of it most likely.
*sigh* Only reason I play Rochelle is that my friend plays as Ellis and her other friend plays as Nick. If I choose either of those characters I get flack for not being "original". And I don't like Coach. Hence choosing Rochelle.
As for L4D, I've only played it once. And Louis and Zoey piss me off, which is sad because my friends play as Bill and Francis.
PP: Not being able to play a character without getting flack from friends for choosing "their" character.