Helga G. Pataki is possibly the deepest, most well-rounded nine-year-old girl ever to set foot in Western Animation. From negligent alcoholic parents, to putting all of her faith in Arnold... The list goes on and on. Her voice actress, Francesca Smith, actually won a Young Artist Award for her portrayal of Helga.
Mr. Simmons, for being one of the first openly gay characters in an animated kids' show.
In the Veterans Day's episode, Grandpa Phil narrates how he beat up Hitler; although he admits it wasn't Hitler and states he actually beat up Joseph Goebbels., someone who was probably worse than Hitler. The rest of his story was even much more awesome, with Phil tricking several Nazi soldiers into eating spoiled meat, and opening a clear path for the Allies to invade Berlin.
Helga memorizing Romeo and Juliet in one night and pulling off the performance with no rehearsal whatsoever. Even The Power of Love can't fully account for that one.
The freakishly huge amount of character development! For one thing, Chocolate Boy starts out as just a chocolate junkie, but then he gets his own episode, where he goes from being comic relief to being a chocolate addict with a back story (in an episode that perfectly parallels many real-life drug stories). There were characters like Tucker, who were one episode wonders, but still managed to get character development into just eleven minutes of airtime. Helga started the show out as a total douchebag who stalked Arnold, but her dysfunctional family made her into an epic tragic love story, all leading up to HOTC! Everyone living in the boardinghouse got their own episode at some point! Brainy is the only character who really never got character development, but his lack of character development totally worked bacause he is the ULTIMATE creeper! Ironically, the show's main character, Arnold, is the only character to really undergo any flanderization (turning into the city's savior in later episodes), but even he had an epic backstory and to top it off, being the city's savior is totally badass!
Arnold's explanation to Grandpa and the other adults in "The Vacant Lot" for why he and his friends just overturned a dumpster full of garbage into the aforementioned vacant lot:
Arnold: You see, this is how the lot looked before we cleaned it up. Before we turned it into Gerald Field - and before you guys kicked us out.
Gerald: So if you want your vacant lot so badly, you can have it just the way we found it: a dump.
In "Das Subway", Grandma is found meditating in her karate gi when she hears news of a subway breaking down, the very same one Arnold and many others are trapped in. She decides to take matters into her own hands and suits up commando style and searches for the subway.
Arnold finally getting back at Helga in "Girl Trouble". Sure, it gets him in trouble thanks to Double Standard, but this clearly shows that there is a difference between Nice Guy and Extreme Doormat.
Stoop Kid finally leaving his stoop, jumping off the stoop when Harold makes fun of him for being afraid to leave his stoop and chasing him while saying "COME HERE FAT BOY! I'M GONNA ROLL YOU DOWNTOWN!" Also a funny moment. Harold's Oh Crap expression just sells the awesomeness.
That was the second time. He actually managed to leave (with Arnold's help) before Harold's scene. Speaking of, Harold apparently was on vacation and missed said scene, making the chase all the more awesome.
Gerald learning to ride a bike and winning the race in "Gerald's Secret."
In Olga Gets Engaged, Helga putting aside her feelings of resentment towards Olga and acting like a sister by getting rid of her lying, manipulative fiance. How does she do it? She catches him right after he finished talking to another girlfriend over the phone, reveals that she knows what he's really like, and when he counters that no one would believe her because of how jealous she is of Olga, Helga offers to redial his other girlfriend and tell her all about Olga. What really sells it is the guy's Oh Crap look and Helga's smug smile as she holds her finger above the redial button.
Big Patty had a habit of bringing these out in others. Rhonda got hers by doing the same thing to a couple of upperclassmen in another episode. She even threatens to beat them up if they don't leave Patty alone.
Hell, the series opens by giving Arnold one.
I'm crazy, and you should never hit a crazy person.
For context's sake: Harold wanted to fight Arnold and the entire episode has Arnold stressing out over this impending problem. That quote is one part of the method of how he fixes it; he claims he's crazy. Theother part?
Lila of all people gets one in "Big Sis," after Helga's attempt to ruin her and Olga's day by sabotaging their horse-drawn carriage turns nasty. One of the wheels flies off, throwing the driver, and the horse goes crazy - dragging the carriage along the ground and running uncontrollably at breakneck speed. Olga starts panicking, but it turns out the ex-farm girl Lila is used to this sort of thing. So what does she do? Leap from the careening carriage onto the horses back in a single bound, grab the reins and pull the horse to a stop. Even Helga can't do anything but gape.
In one episode, Phoebe is turned into a laughingstock when she accidentally farted during a school assembly and became a shut-in because no one (except Arnold) would let her live it down. After her classmates and Mr. Simmons fail to cheer her up, Arnold manages to convince her to come back to school. That isn't the awesome part. The awesome part came when Phoebe marched on stage during another assembly and called out the entire student body for turning her into a one-dimensional joke, admitting that even she would've laughed if it had been someone else, but that it's not fair for all her hard work and accomplishments to be treated like nothing all because of a simple, human response.
Phoebe: (to the school) I'm not that one who has anything to be ashamed of. You are.
Bob calls Arnold an orphan during a Parents' Day competition where Arnold bring his grandparents, which visibly hits home for him. In retaliation, Helga tells Phil how to take him down during the final part of the competition.
In Harold vs. Patty, Harold loses to Patty in the Hillwood City Arm Wrestling Tournament. Sid and Stinky once again proceed to make fun of Harold losing to her. Harold decides he's had enough of their rudeness and starts shouting at them. (Doubles as an Funny Moment.)
Harold:(yelling) SO WHAT IF I LOST TO A GIRL?! Patty's the best arm wrestler-
(he grabs Sid and Stinky by their shirts)
Harold: -in the whole city and she's my friend! I'm proud to lose to her, and if anyone has a problem with that, I'll pound them!
(Harold smacks Sid's and Stinky's heads together and they fall to the floor)