I believed that men were physically incapable of crying.
There was an air vent in my room up near the ceiling, and I thought my mother could watch me through it, somehow.
Because my neighbor Lisa Perez told me so, there was a time when I thought that moss was gravity.
As a kid, I once got hold of my mother's unattended lit Lucky Strike cigarette. I picked it up, clamped my mouth on the unlit end, and blew. Unclear on the concept.
I had a set of magic markers that I believed were truly magic. Their powers were a little nebulous, but I treated those pens with reverence and kept them in a bathroom cabinet.
Back in the day, some cereal boxes included a novelty cardboard record you could cut out and play on a record player. Since the medium was somewhere between paper and audio, I thought if I drew pictures on those records, they would somehow play a narration of what I'd drawn. Spoiler alert: it doesn't work.
Credit cards were expensive to buy, but once you purchased one, you could get whatever you wanted with it. (Wouldn't that be nice?)
Believe me when I say that this is an incomplete list of my misperceptions and delusions. And I'm sure I'm still adding to it today, fooling myself here and there in ways I may never even recognize.