I dont know of anyone literally confusing the two but I know that when I was in therapy for severe depression and anxiety, they asked which I wanted to focus on and I said anxiety. It wasn't that the depression wasn't bad it was just the anxiety was what caused me the most problems - in terms of panic attacks and making me vomit and nauseous. I think in the long run, I ended up treating the symptom rather than the cause though because depression was what was making me so anxious. If I wasn't so depressed, I don't think I would have been as anxious because my anxiety stemmed from "irrational" ideas that I had from my depression. Not sure if that makes sense but, you know?
I've never heard of Buspar so can't help on that one, I'm afraid.