Too familiar or too superficial?

Picking up on a running theme of late, and following from Doug Stockdale's comment on my wet weather post, is the idea of becoming over familiar with things.

For residents of Northern Europe, rain is an everyday occurrence (OK, maybe not every day, but pretty frequent), whereas in sunny SoCal it's more like a desert. As Doug points out, rain for him is pretty unusual.

So can I be too familiar with rainy conditions. Have I blocked out the rain effect so that everything looks the same to me wet or dry? Can we start to tune out subtle variations because they are too familiar to us? That may not be a bad thing, instead of observing the superficial differences (in this case the weather), we might be able to get past it and deeper into seeing the subject. On the other hand, it might be that an important part of the character of a subject is lost to us as we've tuned it out.

I think I may have to make an effort to walk familiar streets on a rainy day (and when I've got suitable clothing to hand) to see if I can spot the differences it brings, delving into this conundrum.