I think everybody probably has some sensory issues -- it's just that they are more pervasive in some than in others. For most of us, we have one or two senses that are bothersome some of the time -- for SPD kids like Josiah, all of his senses (or nearly all of them anyway) are out of whack nearly all the time. When it's less pervasive, it is simply less disruptive to your daily life. It's more socially acceptable to be offended at smells than to be unable to sit still because your vestibular system is driving you crazy, or to make loud noises because you need more auditory input, or to crash into anything and everything so you can get some more input in your muslcles and joints, or to do all of the above at the same time nearly all day long.
Don't forget to stop by Hartley's Life with 3 Boys to read 30 Stories in 30 Days, guest blogs from 30 different families about their experiences with an SPD child.