I was putting my drill bits back in the case wrong for a decade until my kid asked why they were all mixed up.
I always just tossed them into the plastic case after a job, thinking the foam would hold them. Last month my son, who's eight, looked at the mess and said 'Dad, the numbers on the foam go with the numbers on the bits, right?' I felt like an idiot. The case is organized by size and I've been jamming them in anywhere, probably dulling them against each other. How many other simple things are we all doing wrong without even knowing?