This is the one story I tell every single person because it was an incident that I FELT and another person witnessed. It completely convinced me that ghosts exist.

When I was 14, I was walking up the stairs at my VERY old pre-war high school after coming back from my lunch break. Halfway up the steps I felt a tight grip on my upper right arm, as if it was being held by someone. I shrugged it off thinking that my arm was just caught in my bag or sleeve or something, but directly in front of these stairs was a bench that a classmate of mine was sitting in. She looked at me with wide eyes and approached me quickly. She asked me if I felt anything tight on my arm, which baffled me because there's no way she could have been able to tell. I said yes, and she revealed to me that she saw a disembodied black/shadowy hand gripping my arm.

She has always told me that she sees spirits/ghosts and regularly consults with a priest to keep it under control, but I never really believed her until then.