Eric gets one when Red's boss's son (who has been hitting on Donna all episode) says that his father is only opening the power plant to burn the rest of the inventory then it will be shut down, which will leave Red jobless again. He starts to walk away when Eric taps him on the shoulder then breaks his nose with a punch.
After failing to remain aloof from Laurie's verbal taunts, Jackie just does what everyone else has been wanting to do, and tackles her. As Hyde puts it, that is where Zen ends and ass-kicking begins. Eric happily declares that Jackie's his new hero.
Eric: You always tell me to be a man. SO, BE A MAN!
Kitty, who for the entire show has been relatively sweet (with a few setbacks) and the constant motherly figure snaps and gives us this beauty of dialogue...
Kitty: What about my last summer with my youngest child? I bet you weren't thinking about that when you went fishing. I bought sparklers for the 4th of July. He loves sparklers, and now he's leaving... WHAT ARE WE GONNA DO, FOR THE 4th OF JULY?!
Red: Uuhh... There's a car-show in Kenosha
Kitty: Car Show? I don't want to go to a !@#$ing car-show in @#$%ing Kenosha. I want three more !@#$ing months with my baby boy. And now they're gone because of your bull-!@#$. WAY TO GO DUMBASS!
In an early episode, a couple of bullies break Kelso's beer tap and give it back to him broken, leaving the party Eric was throwing without any beer. When they demand their money back because they were promised beer, Kelso tears into them & lets everyone know that they are the reason there's no beer, but Eric gives the money back to them, but not before tearing up the bills. Considering this was one of the first moments that Eric showed any spine in the show, it's all the more impressive.
This was perhaps topped by Eric, whose lack of physical strength was a Running Gag in the show, kicking the shit out of a football fan who had been harassing him throughout the game & continued afterwards. Red had been harassing Eric during the game, but stopped after the final whistle, merely seeing it as banter between football fans, but the other fan continued. When Red tried to intervene, the fan asked if Red was going to kick his ass.
Inspired by his son's streaking, Red finds the courage to publicly criticize President Gerald Ford for pardoning Nixon.
When Kelso finally tells Jackie off for being demeaning to him in "Everybody Loves Casey" . It also shows that he's not just a pig, that he had reasons for his actions - and the whole thing is dead serious.
Made even more awesome by the fact that it doubles as a He Really Can Act moment for Ashton Kutcher, who plays Kelso.
To elaborate: In Season 6, Jackie's mother, Pam, has been revealed to be dating Bob. Donna and Jackie are not okay with this, and try to break them up. When Bob finds out, he confronts the gang and tells them directly that as an adult, he has the right to date whoever he wants, and that he doesn't need his own daughter's approval for it. Eric and the other guys applaud him for this.
Hyde gets his in the third season when Jackie dates a guy in the attempt of making Hyde jealous. Said guy reveals to Hyde, who was completely nonplussed by the tactic, that he's only in it to sleep with Jackie and then dump her, and when he's undeterred by Hyde pointing out what a dick move that is, Hyde's only response is to mutter "...aw, no" before taking him down with one punch.
Red finally letting Hyde live in his house...all the while cursing his ass off!
Red: I am tired of being f##king Santa Claus!! Steven, you get your s##t together, and you get your ass in the Goddamned car!!! We're going! F##ker! Now, Goddamn it!! MOVE IT!! Hyde (really scared): Okay. (automatically runs out of his house) Kitty: You are just the sweetest man alive. Red (taking one last look at Hyde's house): F##K!!!
When Red announces that he's kicking Hyde out in "Reefer Madness" at the breakfast table, Eric, after attempting to say something along the line of "bullsh*t", screams"I'M VERY MAD AT YOU!", and leaves. And unlike when Eric called out Red when Kitty was supposedly pregnant, the audience cheered.
Heck, Kitty gets one in the next episode. After Red refuses to ease up on rules in the house when he learns that Hyde (and Eric) have done pot, Kitty openly announces that she's quitting her job to be a stay-at-home mom to regain her home. Really, you should see the scene in full.
When the boys, led by Kelso, who initially was told he couldn't come with them to Canada, sing the Canadian national anthem. Any Canadian, despite this being a comedy show, probably was reduced to tears or filled with homeland patriotism after watching this.
At the start of season 7, Red is annoyed that Eric is still bumming around the house after his wedding to Donna fell through and wants to know what Eric plans to do about Donna and his future. When Eric doesn't know, Red tells him that until he comes up with a plan, he won't be getting any food-an especially harsh punishment because that night they're having fried chicken. At dinnertime, Eric strides into the kitchen and says the following:
Eric: OK, I'm here to earn my dinner. *grabs plate and sits down* What am I doing about Donna? *takes a drumstick* We're hanging out. What am I doing about my job? *takes a biscuit* I quit! What am I doing about my future? *puts some salad on his plate* Nothing. When am I moving out? *Plops some mashed potatoes down* *Beat* Make me.
After Bob gets kicked out by Midge. Red showing what a Magnificent Bastard he is, pretends to be hurt so he can get Midge to come to his aid so she can leave the door open for Bob to dash in.
Red: Help, Midge! I'm trapped under this very heavy branch!
Midge: Oh my god, Red! Are you hurt?
Red: GO, BOB, GO!
Kelso literally splicing the first Laurie scene together in his mind to form a hidden message implying that she wants him. For a dumbass not only is it well thought out, but it shows major foreshadowing in Kelso's part since he later ends up cheating on Jackie with Laurie.
In "Dine and Dash", Eric and Donna run from their table, in slow motion, as the waiters and waitresses try to stop them. Then they get back at their friends for leaving them at the restaurant with chocolate super lax brownies. Doubles as a Crowning Moment of Funny.