I'm really good at looking at the cocking lever on my Zeiss Ikon folder and thinking "Lever has 'moved down', it must be cocked", because most of my other cameras that have a similar cocking lever mount such that the cocking lever is rotated about a quarter turn or so clockwise.
It cocks and travels exactly the same as all the other lenses I use with a similar functioning shutters, but my mind keeps wanting to map that as "Push shutter lever down", not "advanced shutter level clockwise". So if it has been awhile since I've used the Zeiss I'll pop it open, look at it, assume I've previously cocked the shutter but then lost what I was looking to frame up. Which in turn tends to lead to me trying to quickly frame something up, and then pressing the shutter release to nothing happening.
Also had been really good at double checking camera, film, lenses, tripod, and such while planning to go out somewhere and setup for more careful and deliberate shots. Eyeball initial framing, set up the tripod, grab camera and...
Tripod plate... For one reason or another wasn't on the head or camera that I thought it was.
I'm overdue for either forgetting filter factor, or flipping filter factor. As someone who is often a fan of a deep red filter, flipping it is a painfully dumb mistake.
Another momentary panic source is the little shutter lock button on my C330. It sometimes gets bumped, but I rely on the lens lock dial since it flips the internal dark cover and has the big obvious red line in the viewfinder, so I rarely think of it and never remember which way it is supposed to be when the camera eventually 'jams' on me as I go to take a photo.