The "impossible" stories--the ones that are hard to share because they're so unbelievable, like being contacted by a dead loved one--need to be celebrated.
It might have to be enough to have the story, for ourselves, knowing that no one could ever feel about it the way we do. They're deeply personal and self-serving. But it can be cathartic to release them. Why should we hold ourselves back from telling them, no matter how incredulous? If nothing else, it might give someone else confidence to share theirs.
We all have these kinds of stories. Though the specific stories themselves remain, respectively, ours alone (or that of the group with whom the experience was shared), their expression is something we could probably all benefit from, as both sender and receiver.
My family was sitting around, at Thanksgiving, and a number of these haunting stories were being tossed around. Regrettably, I began playing armchair psychologist in an attempt to explain away the "ghostly" nature of these memories or incidences. I wish I had just listened.
Surely, on some level, we all understand that our I-swear-to-God type stories can be picked apart. But how constructive is that? The act of letting the story pour out of us, despite its lack of scientific evidence or corroboration, is the vulnerable and courageous act that makes it important. It's not what we say, but that we are compelled to say it.
We can't always bring ourselves to say it. Maybe Halloween (like religion?) acts as a sort of collective acknowledgment of impenetrable stories and anxieties. A pass to indulge in our superstitions and unapproachable beliefs, openly, for a time. A tricky treat.
So yes, the Ouija board moved on its own. The lights flickered at the mention of someone's name. The figure did appear in the corner, then vanished. The clouds did part to reveal a rainbow. That song did come on the radio just then. It happened just the way you say it did, and for the very reason you claim.