I think it may be a palate thing... most rubs have some spice in them and thus, the resulting products would have various degrees of heat. So, if one were like most people, they would find that extra bit of fresh ground black pepper to be like little fireworks in their mouth-- perhaps a cold beverage to put out the fire after a few bites.
I, and many of my brethren find pepper to be mandatory, but prefer the sublime flavors or Jalapeños, Habaneros, chipotles in adobo, sriracha, and various other concoctions of incendiary flavors.
Or... it could be that you are actually eating at places where they cook with real food. I have been to many restaurants, I use that term loosely in this case-- you know places where teenagers cook under flashy neon signs and call it gourmet, that served "hot" sauce that were not. If one were to begin to think these tangy vinegar based sauces were indeed "hot" then a real spice might be a surprise! I had the Hell Fire Habanero BBQ sauce on my boneless riblet tiplets platter locally and the waitress was amazed when I drank the sauce from the ramekin.
Not hot...
Keep going brother... one day you may seek out dishes like Spicy Tuna Drano Balls or sauces like Endorphin Rush or even the more common sauce with subtle heat Sriracha.
Trust me... this hot thing can be an addiction.