yup, fraid so... they work by suggestion, and (more often than not, ) cheating.... among certain groups of people they can trigger psychoses and neuroses, not due to the boards themselves, but due to the suggestions implied by the use of the board... in other words, it is the persons belief in the board which causes the damage... if used sensibly and with the right attitude, the boards are harmless... they were invented as a parlour trick... unfortunately, it is rare that the boards are used sensibly, and with the right attitude...
I've played a few times, and I know I didn't move the glass, but how can you say for definite that one of your friends didn't? Admittedly, it was only four of us, and the others were crying etc, but I still don't trust my friends that much to say that the supernatural must have been involved.
I like the fact that you're condemned to hell once you've participated in the use of a Ouija Board though 🙄