Keith - that would be a nice excuse, but I have more general form of left-right confusion. If my wife asks me which way she needs to turn next while driving down the road, I may instantly know the correct answer. If I gesture with my hands it's fine (except she can't see me because she's looking at the road). But if I blurt out the answer, I often _say_ the exact opposite of the correct answer! I then quickly realize that I said the wrong thing.
I have a lot of trouble convincing her that I'm not confused about the direction: I'm just using the wrong _word_ for the direction. Needless to say, she doesn't find this distinction very helpful.
Interestingly, if I don't quickly blurt out the answer too quickly, I'm likely to say the correct answer even without conscious self-correction. It's as if some part of my brain is using the opposite definitions of these words, but the part with the correct definitions gets the upper hand, given a second or two. I think this is connected to me being left-handed. It's pretty irritating.