Yup, grolby, it's mostly a matter of taste, not what you need for a particular situation. As a teenager, I was into road bikes. There were no BMX or mountain bikes yet, anyway. I rode the narrowest tires available sometimes, and at other times, I rode tubulars, which are normally very narrow. Now I'm older and often carry stuff, and for those two reasons, I prefer 28's to 32's, but I still like to jump on my old racing bike (with narrow tires) from time to time.
I do ride some rough trails on my road bikes. I still haven't gotten around to getting a mountain bike.