I'm sorry I stopped laughing for now and am going to try and respond.
Dogs become surface specific, when we first have them go out it's in our garden because we don't want them exposed to outside germs and such until they get all their shots, they get use to going there. Unless you teach your dog to go on cue, like saying a word"when" they are actually going, and take them to diff surfaces and areas out and about, then they go in your garden, and that's all they know. Pups who are weaned are taught by their moms to move away from the living area to go, she stops cleaning up after them when they no longer are consuming her milk, this teaches pups to not soil there living area, if they do not get this important lesson, you have a dog that doesn't care if it goes in your den (ie..your home). The secret to potty training is "supervision", if they don't have a chance to go in your den, you always take them where you want then you are teaching them. If you can go to
http://hssv.org/ look at behavior and go to dog..it will let you read all about it.
Dogs become scared..modest if someone has distracted them with a strong tone or accidently raised your voice when they were in the act, it could be something simple as a pine cone hit their head and they don't want to go in any area cause it's always safer where they are..there are many things I can't address here, I don't have room. I always make my dog go b4 the walk that way she doesn't go on someone elses property, but when she was small she has been taught to go on concrete, asphalt, grass, broken rocks, sand, plain dirt and the curb area, since she goes everywhere with me, I had to make sure she would go if we got delayed getting back home.