A customer's stripped pedal taught me to check the obvious first
Last Tuesday a guy rolls in with a MTB pedal that won't tighten, so I grab my torque wrench and start fussing with the crank arm for 10 minutes before I look closer. Turns out he had the pedal on the wrong side, cross-threaded it, and the aluminum threads were dust. Why do we always blame the tool before we check the simple stuff like thread direction?
Man, I once spent a solid twenty minutes trying to true a wheel before realizing the tire was just flat. The hub was fine, the rim was fine, the whole thing was a big fat distraction. My brain just defaults to "it's broken, fix it" instead of "maybe it's just dumb." At least you caught it before you torqued the crank arm into a pretzel like I did with a seatpost once.