The left side of my brain does not trust the right side. This is true the other way around as well.
Very excellent goodly scientists, all over the place, from everywhere, believe this is the cause of people getting cross-eyed. The left side and right side eyes are keeping an eye on each other. It is called Janus Paranoia.
To be fair, people not interested in dogma believe it is the left, or right side of brain being taken over my shadow demons.
(some may think this belief insensitive, but remember, this is hardcore truth, with Science! Well, the demons are some crackpot theory.)
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Acronym Legend
OS = Older Son, YS = Younger Son
The most important two acronyms I know.