I notice that sometimes in certain shops, houses, etc. that a large portion of the owner's items are available to just 'take', while other items remain marked as 'stealing'. I'm just a little confused at being able to walk into a shop and simply take half of the goods right in front of the owner. Is this just a bug or is it because I have a good standing with the owner or something? If it's a 'good-standing' related reason I guess I still don't fully understand the logic behind being able to more or less 'rob' the owner legitimately.
The more people like you, the more willing they are to let you "borrow" their stuff (and sell it back to them, in many cases).
The higher their disposition (there are 4 ranks), the greater the value of items they're okay with allowing you to take.