Never heard of Flash Forward. Not surprised about Heroes. I stuck with it, mostly as there was nowt else on its timeslot. Did seem to suffer a kill shot early on and spend the last few seasons dragging out its death scene.
Gave Lost a good go, but had to give it up because the telly I watch I have a finicky thing with, I like something to actually happen. It kept promising and failing to deliver.
The execs often rattle the geek viewers with what they choose to cancel though eh. How could Firefly get shot after one season, but that diappointing Smallville keep going. I keep buying the DvDs out of a similar reason I used to go a certain crappy nightclub every few months. The memory of how dreary it was would fade to the point "hmm, can't have been all that bad, lets go back." Then all start sentences with a vague "I guess" before making an observation beyond thier educational maturity, moppity absorbing guilt that doesn't belong to them, leaping to negative conclusions about "friends" while continuity require significant issues be shrugged away at the start of an ensuing episode, all the while staring at a wall so they can point thier back at whover they're speaking to. Hmm, should check Amazon to see when the next season is available.