But as we found in the first scene of Season 10, all the events going back more than 30 episodes had been Pam's dream.
The plot twist was instantly assailed by critics and quickly became a punchline. Decades later, people who never watched "Dallas" roll their eyes and talk about how crazy it was.
Crazy like a fox.
Was it dumb? Sure. But it saved the show.
"Dallas" would not have run for 135 more episodes without the dream-season wipeout. New producers and writers put the show in a very bad place in Season 9, and the shower scene put it back on track.
It was like ripping off a bandage. It hurt like heck, but then things got better.
"I don't think it would have run five more years if I hadn't come back," Duffy said. "But as much as I would like to think it was me, [executive producer] Leonard Katzman left when I left. And when Leonard Katzman left, the heart left. The quality control left. The brains behind what made 'Dallas' work on a regular basis left."
Katzman's successors "wanted to reinvent the wheel." He agreed to return when Duffy did and righted the ship. "The people who came in and ran the show that season just didn't get what made 'Dallas' work," Duffy said.
Cynthia Cidre, on the other hand, does get it. She's the executive producer of TNT's revival of the series, which premieres Wednesday at 7 p.m.
It's not a remake; instead, the show picks up 21 years after the series ended with some of the same actors (Duffy, Larry Hagman, Linda Gray, Ken Kercheval), grown-up versions of the kids from the 1978-91 original, and a bunch of new characters and stories.
It's "Dallas" in overdrive. The 10-episode season burns through as much plot as a 30-episode season did back in the '80s but maintains the spirit and the fun of the original.
"No one can write 30 episodes well," said Cidre, adding: "Every episode will have three to five cliffhangers. It's crazy plotted. Your head is spinning."
"Dallas" was never great art, but it was great fun. It did what serials were supposed to do entertained viewers and kept them on the edge of their seats.
TV has changed a lot since 45 million to 50 million viewers regularly tuned in to "Dallas," since 83 million Americans and more than 300 million viewers worldwide tuned in to see who shot J.R.
But "Dallas" still works. Because Season 8 was all a dream.
Scott D. Pierce covers television for The Salt Lake Tribune. Email him at email@example.com; follow him on Twitter @ScottDPierce; read his blog at sltrib.com/blogs.tv.