I have many.
I was helping my nana move into her new apartment. I had to go in the elevator alone and and makes a loud buzzing nosie. So when it would buzz, I'd jump and scream a bit. I did that four times. I even bit the inside of my cheek and said "here it comes. It's gonna buzz." I jumped anyway.
When the pop-tarts pop out of the toaster I jump and scream too.
I jump during harry potter too! I've seen those a thousand times! You know how in the fifth one Harry and Dudley are in that tunnel thing and the dementor starts to strangle harry and the music gets really loud sudddenly? I jump there too.

What are some weird and slightly idiotic things that make you jump and/or scream?

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