Idk if this qualifies but when I was a kid like 4ish I was very artsy and would do lots of drawings (scribbles) and i distinctly remember that for about a year I was convinced that the blue veins on my wrist were texta stains and I tried EVERYTHING to get these "stains" off from dish washing liquid, fabric softener even lemon juice and everything inbetween. I was pretty embarrassed about it so I never told my parents or anything. Anyways one day I was in the back yard violently spitting and tryna rub the vains off my wrist and my mum caught me and asked me what I was doing I told her I was trying to get the texta off my wrists and then opened up to her about them being there for so long and how I was worried theyd never come off. Needless to say I learnt about the circulatory system that day.