I don't know about ghosts but in Ireland we used to believe in faeries. Here's an interesting/infamous story I posted on here before
http://en.wikipedia.org/wiki/Bridget_Cleary
It's absurd but you will be hard pressed to find somebody who's prepared to knowingly cut down or damage a Faerie Tree. If you ever visit and notice a farmer's field with a a solitary inexplicably in the middle, it's because it's a Faerie Tree.
It's probably just Karma for the Irish. If you go about worried negative things will happen, they may very well do.
Same with ghosts, if you're open minded and go about looking for unexplained occurences, you're bound to find something. Maybe they exist, who knows?
That said, I did see a UFO one time. Me and my dad were driving to my Grandmother's house In Newtownards one winter evening when I spotted a strange cluster of lights hovering adjacent to Scrabo Tower. We kept looking at it and were so intrigued we pulled over at the side of the dual carriageway. We watched the lights hover for a few minutes and then they travelled incredibly quickly in our direction. The object shot over our heads in silence, 100 ft up, was perfectly triangular and had a blue jet coming from the rear. Could've been the military testing a 'harrier' type aircraft but why did it hover beside an obvious hazard? Why was it silent? Ps, neither of us are mad or particularly into extraterrestrials etc.