Oh, come on, at least you got six seasons out of it! That's a fantastic run for any show.
Just try to watch Firefly, jPod, My So-Called Life, Drive, Carnivale, Freaks & Geeks, Joan of Arcadia, The Sarah Connor Chronicles, Primeval, Kyle XY, Strange, UnDeclared, Invasion, Wonderfalls, Swingtown, Jack & Bobby, Kidnapped, The Middleman, Reunion, Traveler, Relativity, Spooks: Code 9, Aliens In America, Grosse Pointe, Keen Eddie, Life As We Know It, The Class, Miracles, Kitchen Confidential, Touching Evil, Dark Skies... or any of the other 200+ shows that were canceled way to early, many of them even with a cliffhanger ending.
I mean, I feel your pain cause I'm a big TV show fan and many, many, many of my favourites have been canceled way too early without any resolution, but you should feel really lucky to have six seasons.