Why are Ouija boards so bad?

I don't believe ouiji boards actually do anything. But generally when people have used ouiji boards that's when the worst things happen, people get harmed, go missing, killed etc. (supposedly) Personally, I did a ouiji board and the gl only moved because we were willing it to. ie we pushed it. Otherwise, why would you need to hold the gl?...the 'spirit' would move the gl itself, if it can throw objects and kill people.....