I swear my charger is not there!!!
I often find myself telling my wife or my mom -"I swear the knife isn't in the kitchen shelf or the charger isn't in the socket by the fridge". This is typically followed by the mom or wife coming back shaking their head, how vigoursly depends on their mood, showing me the the knife and charger were exactly where they said it was (and where I checked it wasn't). It's embarrassing to admit but happens to me so often, typically at least once a day.
Why does it happen? Often, it happens because 1) we see (and hear) what we want to hear, and 2) our minds are trying to process so many competing thoughts that we don't end up paying full attention to what we are doing!
It's almost a daily reminder to self that at work, irrespective of how much we may believe we understand something, it's important to relook and reflect on things for unconscious and familiarity bias can step up. The other takeaways is it's useful to get a neutral perspective as someone who isn't close to the problem (or wedded to the solution) almost always looks at things more objectively.