When I was a kid they were inexpensive and easily available, maybe a good alternative to TV on a rainy day. People seem to really rant against them. Cardboard with plastic pieces and weird symbols?
This is true, cheap entertainment on a rainy day. The problem is, if you ask, sometimes you just may receive. To be honest, you have no idea from whom you are receiving. Too many people have found that it is an instant doorway for demonic spirits. I can't tell you how many hauntings I have investigated that started because some idiot was playing around with a Ouji Board.
I have never owned a Ouija board but I know a family that had one when I was a child. As far as I know they are the only ones that had one that didn't have something bad happen. The reason, I believe, is that they didn't take it seriously and, perhaps most important of all, they didn't use it to try to contact any entities or spirits. They just saw it as another toy, like the Magic Eight Ball, that you ask questions of on a mundane and juvenile level.
Greatly contrasting that, I do know of one Ouija board incident, the only one that I can speak on personally, because I was there at the end. All I'll say is that after some friends had used the board to contact a spirit involving a stolen head stone (while I wasn't involved in any of it), they decided (after a string of very unpleasant events) to return the piece back to the grave site. While they had obviously gotten the thing to the second story of their house, it seemed almost impossible to move it out, it was so heavy. The decision was made to drop it out a window to the lawn below and then move it to the car for transport. When it landed, it left a dent in the ground several inches deep because it didn't land flat but top first. Then the stone was lifted and placed in the car and driven back to the site where is was somewhat sloppily placed back.
When we returned, a red haired dog with a short coat, that no one had seen before, was standing at the impact point in the yard, scratching at the earth and baying up at the sky like they show wolves doing in the movies. However, it was the kind of howling that dogs are known to do when someone has died.
True story. There's more to it but it is unique enough that I may want to use it later. Anyone on the web could read it here and steal it if they wanted, so I'll have to keep it under wraps.
If you use a ouija board and you don't want to open the door to negative energies, then you should say the Lord's prayer first and keep your thoughts and questions on a high spiritual basis. if you don't you open the door to malevolent spirits/energies over which you have no control and sometimes there are frightening episodes. Ouija boards were originally used in seances by mediums who were sometimes sincere and some were cons.
There's a reality to rant; the truth is the Ouija board is not inherently dangerous itself, but the intent with which one uses it can cause a Pandora's box of problems. The reality is that it facilitates communication based on the intent of the user that is picked up by nefarious spirits upon the astral plane. The vibration is far Lower and like attracts like. However, use of the board regularly will also cause one to build up and perhaps allow a portal of energy to which is used by nefarious spirits. So, the board as an object is not dangerous but the intention and energy that surrounds it can be. Demonic spirits will rarely enter through a board, their level of intellect is far superior, but they will use another spirit force to facilitate contact and gain trust. One case I worked on did not manifest till 9 years later, but slowly the oppression happened over 9 years.