OCD symptom i struggle with but don't see talked about a lot: inability to trust your own memory and/or perception.
as an example: i put my headphones in my bag. i say im sure they're in my bag, but what if i imagined putting them in my bag? i have to check, so i stick my hand inside and grab them. but then i have to check *again* because what if i just so happened to have another object shaped and sized exactly like my headphones that i just forgot about? so i have to pull them out of my bag and look directly at them to fully confirm they were in my bag
this is a fairly benign example but this also happens with other worse scenarios for me and it's. not fun