I had to laugh at this. Partly on the video, but mostly out of a memorable one I witnessed.
Remember the haunted house one, where you had a person stare at the room, looking for a ghost?
Well, at work, the department assistant pulled it on everyone. The best one was a fellow who was a very analytical guy. You could see him working out in his mind where this hidden ghost would appear. When the face jumped out on the computer, he did almost the exact same thing as this girl...his chair went backwards, he fell, then jumped up and screamed like a girl and ran out of the office.
We laughed and laughed for days.