Been through a few conversations now and I'm picking things that seem like polite or relevant questions and I'm coming off as a sarcastic ass. So I guess it's safe to assume that the bottom selection is the angry teenager response?

I think it's standard BioWare procedure now that bottom of the dialogue wheel//options means your character will say that thing in the most dickish way possible. Unless you're in a submenu that is just you asking for a bunch of exposition.

Typically, when there are three options on the right side, it follows the DA2 system. Top-right is diplomatic/helpful, middle is humorous/charming, bottom-right is aggressive/direct. That doesn't mean bottom-right is automatic disapproval. It depends on the demeanor of your companions and the situation.

Yup, one of the more questionable features of the dialogue wheel. Generally, top right is nice, middle right is cheeky, bottom right is mean.

I picked the bottom option every now and then when I thought the situation called for it and in most cases it was usually just an aggressive option. I rarely noticed disaproval drops when I picked it and it usually wasn't outright dickish. But you do have to remember that the bottom option is more often than not the "renegade" option, so it's best to avoid those responses if that's not what you want.

Two aspects of DA2 I wish they kept, one of which is the "Friend or Rival" system, the other being the dialogue system. I liked how if you were keen to a certain response (Diplomatic/Sarcastic/Aggressive), it would start incorporating that into automatic responses between dialogue choices. In most other BioWare games, there is a weird disconnect between one line being said, and another. You can select the aggresive response, and your character will just slip right back into neutral in the sentence immediately afterwards. I want my dude to be sarcastic and humorous nonstop, taking nothing seriously.