I've had the same experience with the Star Wars prequels. I showed the original (theatrical version) trilogy to my 5-year-old son, and he fell in love with them so much (indeed, he became obsessed with them) that I finally relented and ordered the prequels off of Amazon, just so he could see the rest of the story. And when I re-watched them with him, I thought, "These aren't nearly as disappointing as I remember them being." They're not as epic as the originals, but considering that they are, in fact, the fourth, fifth, and sixth entries in a movie franchise, they are stunningly good. Usually by the time you get to Whatever 4, it's just a self-aware, winking-at-the-audience parody of itself. (Granted, Anakin building C-3PO, R2-D2 saving the Naboo ship, and secret Death Star plans were nothing more than winks at the audience, but the prequels also contained their own new mythos that managed to expand on the original mythos while being kinda sorta consistent-ish with it.)