Is This Rude and Weird?

I've developed a certain habit that recently occurred to me might seem off-putting. When people say, "Hey, how are you?" I respond, "Fine, thanks." I don't ask them how they are doing. I started doing this because people always ask me the how are you question like when we're passing through in the hall, and I just don't think it's a good place to be getting into a whole discussion; if they really wanted to know how I was doing, they would suggest going out to lunch or something, not expect that I collapse all the myriad of my constant woes into a sentence. Thus, I don't feel obligated to reciprocate the question.

I've developed this habit so long that now I just don't ask how people are, period. I wonder if people think that's weird.