h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I have no idea how locale -specific what I know is... so this goes for the southern Appalachian area of the US.

~Gates. Leave them as you found them unless you *know* they are supposed to be open/closed and they aren't. A gate near a road probably isn't supposed to be open; however, some farms have fences that are arranged so certain areas can be closed off to livestock if necessary, such as a gate near a road. If in doubt, find the owner of the gate and ask them. NEVER do it yourself. And don't go into fields unless you know you're allowed to. That's just rude.

~Trash. If you see it by the side of the road, pick it up. If it's inside a pasture, see the above thing on gates. And don't leave it behind.

~Trails/hiking. Be sure you have permission if it's not public land. Sometimes people are touchy about their land - and rather attached to their rifles. Also, be sure you wear proper colored clothing during hunting season so people don't mistake you for a deer or goose or duck or whatever.

~Animals. It depends on a lot on the animal and the area, but generally one should keep their dogs to themselves. With feeding/petting animals by the roadside, the general rule is that you shouldn't go much further than just looking unless you have previous permission from the owners.

General personal relations:

Southern Appalachians are friendly people as a general rule. Until you give them a reason to do otherwise, they'll help you out whenever you need it and expect you to return the favor. Ways to get out of favor include:
~showing off. This includes both talking about personal endeavors and merely trying to talk about ideas too soon in a relationship. Stick to small talk for a bit.
~making fun of the accent/heritage/family.
~referring to southern stereotypes in a joking fashion - UNLESS they are fully aware that you're joking. This includes everything from referring to the confederate flag and assuming everyone in the south thinks that the war was never over to racial issues.

It's a bit weird, true, but those all revolve around trying to avoid confrontation. Also, don't try to become too friendly too quickly. That's seen as a kind of falseness. And when you speak to someone, even just to say hi, look at them in the eyes. Anything else is seen as evasive, like you don't trust them.

More when I can think of it...