babywipes, water, a snack, a knife, and in my pocket I always carry an altoids tin with a couple of teabags, some hard candy, a bullion cube or 2, and a way to make fire. This is a lesson learned the hard way, went on a ride with a few friends I hadn't seen in a while, on a trail I was very familiar with. We were so busy catching up that we missed the turn back to the trailhead, and had to spend the night in the woods with no food or fire and nothing in our bellies. The situation may never arise again, but if it does I will be prepared.
FYI, it is spelled W-H-O-A.