That time I had to explain shutter lag during a toast...
At my buddy's wedding, his uncle shoved an old film camera into my hands during the speeches. He thought since I fix cameras, I could make it work right then... I had to quietly point out the shutter was stuck open, which is why all his photos were blurry. We had a good laugh about it later, and I showed him how to check for that issue. It reminded me how often people don't know the basics of their gear.
That's actually pretty wild they wouldn't check the equipment first. You'd think for a pro they'd make sure everything was perfect. Kinda ruins the whole point of inviting them.