Oh man this hits home. Had a guy bring in a Canon AE-1 last year and he stood right at my shoulder the whole time telling me which screws to touch first. Like buddy, I've done this a hundred times, the mirror doesn't need a babysitter. The funny part is these are always the people who never actually shot the camera much, the ones who do just hand it over and let you work. I just talk real calm and keep my hands where they can see them, seems to settle them down.

Wrote a scene last month where my main character gets fired from the bakery she built from nothing and I literally stopped mid sentence because I felt bad for her lol. Finished it after like 3 days of avoiding my laptop and it ended up being the first thing I've ever had accepted by a journal. Now I keep a note on my phone called "be mean" and every time I start a new story I read it first. One thing that helps me is asking what my character would never admit out loud, then making the story force them to say it. Also tried writing one where the love interest just leaves with no explanation and no goodbye, no text, nothing, and that was brutal but so good. So yeah its not just you, it's a habit you have to keep catching, but it gets easier once you see how much better the writing gets when you stop saving them.