Over the years, I've seen my grandfather do a number of strange things. One time, while watching football on TV, he sat there yelling at the players. I couldn't help but say, "Grandpa, they can't hear you." He replied, "Oh yeah, that's right, they got their helmets on."
An even stranger event occurred during a family dinner. Grandpa (still sharp in mind and spirit) filled up his plate with food, grabbed a fork, walked by the sink and promptly emptied his plate into the basin. Acting as if he was washing dishes, he caught himself in the act but not before Grandma began yelling at him. I don't recall what Grandpa did next, but I suspect he wished he was wearing a football helmet.