I, for instance, take my coffee black, and have done so for almost as long as I have been a coffee drinker. When I started drinking coffee at 18, I usually added half-and-half and two packets of sugar. One day I tried it without sugar, and found that the cream complimented the coffee a lot better on its own. After some time I eschewed cream and haven't looked back since. I even drink espresso black.
I can tolerate milk or cream in my cup, but I have become an enemy to sweetened coffee. To me, combining the sweetness of sugar with the smoky bitterness of coffee is too much of a flavor clash. That's the taste I've acquired. I also am not a snob about my beans--I'll drink whatever's sloshing in the pot, as long as it at least reminds me of what coffee should taste like.
When a friend visited from the States last year, he had enough of my exasperation in cafés: "No matter how many times you order it, people are going to look at you funny. You can't change that. Get used to it."