cue X-Files theme
Clearly he is hiding something!
But seriously, while I have seen no credible evidence of recent extraterrestrial visitation or ancient aliens manipulating/guiding humanity since the dawn of time, I enjoy the stories. Claiming someone's anecdote, whether first-hand or 17th-hand, is a complete fabrication from the get-go still isn't a sound response.
I feel the same way about cryptids and ghosts, though not about UFOs. Admittedly, that's probably because the vast majority of "UFOs" I've seen have been blurry pictures of easily-identifiable objects, such as oddly-shaped balloons or ultralight aircraft obscured by cloud cover, and I'm not easily fooled. As a result, I'm not quite as mystified by those stories as I am by the others.
Actually, now that I think about it, I've listened to many odd anecdotes in my life about ghosts and out-of-place artifacts, and I have to wonder if I should just nod my head when listening. Denying their validity outright is just plain rude, but sometimes the storyteller doesn't remember things correctly, and certain details tend to send up red flags in my mind. I don't like truth getting turned into myth because of poor memory, and I've grilled people before about as many details as possible, particularly when the subject is out-of-place artifacts. Is this something I should be doing?