When I was aroudn nine years old, at Cub Scout camp, I was looking up at the night sky. One of the first times I was alone (kind of...on the other side of the campground) looking up at a night sky not overwhelmed by the city lights. I was simply awed by the number of stars in the sky. And I very clearly recall how I suddenly wondered if one of those stars had a planet going around it, and if on that planet it was nighttime, and if there was a kid of some kind, like me, looking up at the stars in the night sky and wondering if someone was looking back at him... I still wonder that now when I look up at the sky on a good night, with no clouds to hamper my view.
As for their intentions, did anyone see the movie "Planet 51"? Kind of a funny flick, but if you think about it, what would happen if the aliens we come across are just like us, but just appearing different, or with different technology? Probably not a good thing... Maybe sitting quiet here is not such a bad idea...