Iowans Love Red Green (Steve Smith noted that Iowa was one of the states which gave most generously during PBS pledge drives to keep the rights to Red Green re-runs). Enough to basically get their own episode, "Twinning." Steve Smith also joked that he could probably get elected governor of Iowa if he wanted to.
Reportedly, while it wasn't overly large, there was a decent sized fandom for the show in Israel, of all places.
The show was also extremely popular in Michigan, which was the first U.S. market to pick it up. No surprise, since Michigan, being just across the border from Ontario, has a lot of cultural similarities.
Growing the Beard: One of the only other shows besides Star Trek: The Next Generation to apply this trope literally. At the beginning, Steve Smith's beard was actually fairly short and trimmed, and as his beard grew out the quality of the show improved. Smith later Lampshaded this fact when he pointed out that you could almost tell what season a given episode was in by looking at his beard.
Besides the literal beard, the show really started to take off in season 4, thanks to two new segments ("The Buddy System", "Red's Sage Advice") and a few new characters that would be regulars for the rest of the series (Dalton, Mike, Winston, Edgar). The show also incorporated more "men vs. women" humor, a staple from there on out.
Heartwarming Moment: When in Duct Tape Forever Harold finally calls Red out on his constant belittling and insults, Red pulls out a photo of himself as a high schooler—and we see he was nearly identical to Harold. Red was mercilessly picked on as a kid, and he's just trying to help Harold grow a spine.
Hilarious in Hindsight: At the end of each season 6 episode, Red told viewers that if they wanted some Possum Lodge merchandise to call 1-800-YPOSSUM, "or if you're a techno geek, check out Harold's homepage on the internet." Nowadays, it's far more commonplace to check out a company's website as opposed to calling a number for information, and more than just "techno geeks" use the internet.
Older Than They Think: Since Steve Smith's earlier sketch series, Smith & Smith and The Comedy Mill, have never been PBS staples to the same extent as The Red Green Show, American viewers may be surprised to hear that the character of Red Green goes back to 1979-80, in segments in which he gave rambling monologues (sometimes accompanied by "home movies") about recent Possum Lodge hunting or fishing trips in a spoof of Canadian TV mainstay B.H. "Red" Fisher. Even in those early days, such characters as Buster Hadfield, Stinky Peterson, Junior Singleton, and Old Man Sedgewick were already being mentioned regularly as participants in the chaos that Red related to the viewer.
Seasonal Rot: While if and how much this occurred is up to the viewer. Steve Smith admitted in at least one interview that the show was intentionally ended to keep this from happening. It was said outright in the last show, on screen. They were ending it while it was still funny so people had good memories of it, to prevent it becoming a Franchise Zombie.
Tear Jerker: In the last episode's advice segment, when after Red says his trademark "Remember, I'm pulling for ya. We're all in this together." line, Steve Smith gets up and has to leave the stage, because he's ready to cry.
Oh heck, the entirety of the episode is a tear jerker.
"Weird Al" Effect: The Red Green Show is beloved in Canada and many PBS markets in the United States, but in the latter country in particular, The Red Fisher Show, of which the Red Green character was originally conceived as a parody, is less well-known.