A childhood belief about ghosts

When I was like 6 or 7 at school me and a bunch of my friends were suppose to go in the bathroom one by one and do "Bloody Mary" and see if you could "see" her. Well i was scared and didnt wanna see her so i didnt do anything. All the other kids came back and said that when they flushed the toliet (like they were supppose to) saw her in the mirror. So from then on for a long time i thought if you flushed the toliet and looked in the mirror you would "see her" so i would flush the toliet and run out the bathroom