Took me about 8 years to admit I was using my multimeter wrong
I always thought you had to touch the probes together to zero it out before measuring resistance, but a neighbor who used to fix radios for a living told me last month that's only for old analog meters, not digital ones. Has anyone else been doing simple stuff wrong for way too long without realizing it?
Found out after years that I was pressing the brake pedal when starting my car because I thought that's what you had to do. Turns out it was just a weird habit I picked up from watching my dad.