Nope, I've never seen ghosts, and I suspect they're a trick of the subconscious... but I can't be 100% sure. Why the subconscious would want to do that, I'm not sure. Plus there's the fact that cultures all over the world have developed ghost mythologies, despite never having seen Scooby Doo.
I have an open mind, except when it comes to those charlatan mediums, tarot readers and ghost experts, who should be shot at dawn and fed to hungry pigs.
Q xx