I wasn't abducted before, but I firmly believe that alien life forms exist. Why? Well on Earth we have life forms (e.g. bacteria) living in very hostile conditions like under kilometers of sea water or high-up on mount Everest. This, along with the fact that everyday we discover a couple of more "Earth-like" planets half the way across the universe is an enough proof for me that statistically it's very probable that somewhere on the other side of the universe there are some bacteria living in a water pond, maybe even as close as Europa!
The part with little green men in silver jumpsuits landing in secret is the one I hate. Let's be honest to ourselves, if aliens ever find us first there are only two likely outcomes: A. We build a very successful interplanetary economic relationship. B. They eliminate us. Let's take a simpler example, during the last couple of thousands of years we had very different civilizations on Earth come in contact with each other and the outcome was always one of the two above. China, Greece and Egypt have enjoyed periods of flourishing economic cooperation. While the Spanish empire managed to wipe out most several civilizations in it's conquest to colonize the New World. History doesn't tell us of "sightings" of Greeks in fancy white robes riding a circular horse-drawn wagon who regularly abducted Chinese people in the 3rd century B.C. and anally probing them later, right?