Of course Jorge, that "never" happens. lol

I guess one of my favorites is leaving the lens cap on, on the inside of the bellows. I look at the front, it's ok, nothing! I make sure the film holder is out, NOthing, I make sure the shutter is open, NOTHING. Then after that brief moment of sickness thinking my lens is broken, I remember to check the rear lens cap. <naughty word here>