I grew up in the '70's during the UFO fad. Close Encounters of the Third Kind and In Search Of... were a big part of my childhood. That interest has stuck with me. I very much enjoyed History Channel's UFO Files, especially the Then and Now? episodes that gave a balanced view of UFO reports and gave debunkers equal time to make their case.
But Ancient Aliens is just dreck. When Erich von Daniken is your most credible 'expert', you know you have a serious problem. The show piles guesswork on top of supposition building up the most wobbly of arguments for why aliens are responsible for everything from the pyramids to the theory of relativity. Opposing viewpoints are never mentioned, nor are facts allowed to get in the way.
Every time the announcer says "Ancient astronaut theorists" you can substitute the phrase "Tin foil hat wearers" and as soon as Giorgio Tsoukalos (aka: the Greek guy with the wild hair) shows up, it is the signal to change the channel.
I do believe there could be something to the UFO phenomena. Some cases, like Travis Walton or Betty and Barney Hill deserve serious investigation. But watching Ancient Aliens will only make you stupider. Having an open mind is one thing. Being so credulous you'll swallow this malarkey is another.
(Rated a 1 because I couldn't figure out how to rate it 0.5)