I hesitate to use the word abnormal or odd, having been tagged too often with those labels myself, but I do think most people would stop themselves before going out of their way to drive by someone's house. I had the impulse myself a few times during a couple of crushes in high school and college, and never acted on it.

How many people on this thread would not be bothered if they learned that what is in effect an acquaintance - not a friend, not a family member, because that is not what a therapist's clients are to them - drove out of their way just to eyeball the house where they lived? Imagine a client of yours did that, or a co-worker you didn't know well. SD has already said she isn't bothered by it, but I would be.

And may I also point out that there is a reason that "curiosity killed the cat" is such a popular saying.