Not weird per se, but it actually happened today. I was helping a friend at a large estate sale. I was filling out tickets for customers and one lady asked me to put her items in a box we had sitting on the floor.
I kneeled down to get the box and somehow my shirt lifted up over my Glock 30 I had in a Serpa holster on my hip. Not one person noticed, even the lady looking down at me. I stood up, put my back to the wall, handed the lady her box and casually put my shirt back over my gun.
It just reinforced my belief that the majority of people are oblivious to what is going on around them.
Brain (Use this one the most)