I've never believed aliens were watching us from their UFOs, but the more science fiction I read, in which humans are hopeless idiots, destroying themselves and their planet, the more plausible it seems that extra-galactical others would watch, take notes, and move on. Still, I gravitate toward natural explanations before extraordinary theories. An Ockham's Razor sort of thinking. (I've googled it, and there several accepted ways to spell Ockham.)