Despite what you may think, I am actually filled with love and compassion, especially for the rare little birdies of the world.
Because of said compassion, I came to the conclusion long ago that some people are not dumb, they're just simple.
These people are unaffected and unburdened by complex or complicated thoughts. Their life's aspirations really don't extend beyond the tips of their noses. When they go to sleep at night, that's it! They are not kept awake by cognition, nor do they wake up with the weight of the world on their shoulders. Every day is fresh and new.
While this sounds desirable, the problem with being simple is that other people have to do all the thinking for your simple ass. You are basically at the mercy of the non-simple, and don't have the mental wherewithal to challenge it.
Some telltale signs of a simple person are: lack of eye movement, smiling for no reason, easily baffled, limited or no vocabulary, repetition of simple thoughts, actions, or ideas.
There is no known cure for simplicity. Just put something shiny and bouncy in front of them, and they'll be ok.