Could be one of the dumbest I do, considering if I die from an ammonia...?
But probably the most consistant dumb thing I do...
~ It's not paying attention to details given out by the "accurate" weather forcaster. (if that's what you want to call them)
This usually leads to not dressing for the weather conditions, properly.
One Muzzleloading day (I know this is bowhunting ???) when I sat in my stand I had "heard" of "rain showers", and I contemplated wearing my rain gear and should have.
The sky opened up with rain and everything including my taint was pruned beyond recognition.
Now - I usaully shoot my muzzleloader after any moisture eppisodes happens, but didn't do it that rainy day.
A couple of days later I went back in the woods and had a nice 6 pointer broadside @ 35 yards and countinued to snap off 5 caps before he finally walked away.
There was no BOOM after the cap because of my moisture problem, live and learn?!!

So the weather can be a DUMB thing not to pay attention too!