Personally, I couldn't care less. But my theory is that it probably bothers some people because to them it looks like a *mis*spelling, rather than a different spelling; those extra seconds it takes them to compute fucks with the flow. I hate seeing actual misspellings in stories (I mean, a lot ... a few are bound to happen, I guess), and it can bother me when trying to enjoy the story. But American/Brit spellings are both familiar enough to me that I read them smoothly and don't think twice about it.

Probably it wouldn't bother people (Americans) so much if they read more literature with both spelling types represented ... it would become natural and not seem like words are misspelled.

To actually address your concern ... no way should you adjust your spelling to accommodate a specific group. As Fraser might say: that's just silly. I can't think of a single good reason to do something like that. We should all be lucky to have correct spelling at all! To complain about correct English spelling because we haven't broadened our experiences ... well, that's ballsy!

debraC