Do you believe in UFO'S?

i personally do. i think its extremely arrogant to say that there isn't another being out there that is more scientifically advanced then us and has came to our planet. ive seen shows like on national geographic chanel that shows videos on ufos and some are pretty damn clear that its some kind of ship. but yet when they show it to "Professionals" or highly educated scientist, they give the most stupidest counter arguments. there was a video on a ufo that its pretty easy to tell its some kind of ship, and when it was shown to the scientist he says, "well that's probably a big bird.".......are you serious?????? i mean even if you don't believe in ufos why is it so impossible that we've been visited before. the universe is infinite, why is it so hard to believe this?