Why tou afraid with ghosts?

i have never seen a ghost but i will share an experience that happened days ago. we were on a sleep over in our friend's house. we were four girls in her room and we we chatting with another friend who is abroad. we had our web cam even though it was very dark because the lights were off. of course our friend couldn't see us. after 30 minutes of talking with her, she was finally able to see something even though it was dark. she saw someone in white clothes. we were surprised because i was wearing white pants that time but she was referring to another place in that room. we turned on the light and we were shocked because the web cam was not pointed in our position. then she said that she still was seeing someone, a ghost. i was very scared that time that i couldn't sleep at first.

I don't know if I saw is actually a ghost, I just blink my eyes again and its gone. If I see ghost right in front of me I might run or shock. Please get out of my sight ghost.

I've never met a ghost, I did not know I was scared or not. I am not afraid of the dark and not fear the place deserted. I'm afraid in the dark and quiet is if there are criminals.