heathen,
i know what it is to want to believe. as cynical, and skeptical as i am of your's and others experiences with the supernatural, i still do want to believe. why you may ask? (or perhaps you're not asking that, but i doesn't matter, i am going to give you an answer anyways): because if ghosts, or spirits as you call them, actually exist, then that means that there is more to the universe than i am aware of. and if there is more to it than i am aware of, then my life would change, because my life would not longer be totally devoid of external meaning. which would be like a drug for me.
so, it's not that i don't want these spirits to exist. i do. it's just that honestly, the most logical and economic explanation is the one that John Doe already gave. these spirits could have a lot more power of humans and the world if they made it obvious that they exist. but they never do. they seem to concentrate on the credulous, and never the skeptical. that says a lot right there.
you said you believe in evil spirits? define evil for me please.
TS