There is the distinct possibility that there is nothing out there hiding. With all the supposed alien activity over the centuries, it is impossible to imagine that not a single piece of alien technology has been misplaced for us to find.
First of all not all crop circles are hoaxs some are believed to be authentic. Second is there any proof that an aliens have multilated any of us. Third, is there any proof of any real alien abductions. I am not ruling this one out I just want to know if it has actually been verified. As for why aliens haven't actually made contact with us yet. Maybe they are studying us, maybe they don't know if we can be trusted, or maybe they want to know what we are all about. Think about this for a moment to them we are the aliens, not the other way around.