When Disney Channel was getting ready to air The Movie, they had a viewer-voted countdown of the greatest episodes they'd already aired of the show, and "Emotion Sickness" ranked #1. Kim and Shego both get Moodulator chips on them that causes them to act according to the control unit's settings, causing some really awkward scenes with Ron and Drakken, respectively. The affection Kim shows towards Ron may seem entirely a result of the Moodulator, but it's certain that she does feel this way about him inside, and the chip just brought it out; this also notably helps setting up what happens between them in The Movie.
Pre-K Ron and Pre-K Kim in "A Sitch In Time" were so adorable.
Ron Stoppable discovers actuarial science (which calculates risk factors), and wants Kim to stop crimefighting (or pretty much anything that could be remotely dangerous) as their odds suggest they should have "been toast" years ago. Kim requests more of an explanation, and Ron tells Kim that he couldn't live with himself if he lost her. Awww.
Ron: Look KP, I just want to keep you safe, because if you got hurt, itís too big a loss to compute. Kim: Thatís the most weirdly romantic thing youíve ever said to me.
Following on from the above, later in that episode ("Odds Man In") Ron learns that he's more of a risk for dying than Kim is and builds himself a "panic room" he refuses to leave, forcing her to recruit Wade to help stop Drakken note who had recently become more successful & efficient due to starting a cupcake business, and treating his organization like a corporation, complete with hierarchy & bonuses and the like with both getting captured. Ron debates whether to leave the room due to the odds of his survival, when his dad tells him that, the one thing he learned from his job is "some things are worth the risk." Cue Ron pulling a Big Damn Heroes moment to save his girlfriend and Wade (which Kim even admitted was quite romantic).
"A Very Possible Christmas" is from start to finish a Kim/Ron love story. note Some even believe that Kim's tearful "I don't know" in response to her mother's inquiry as to Ron's whereabouts was the first sign that her feelings for him were more than platonic. Heck, just throw in all Kim\Ron scenes, and there's quite a few more than you might first think.
The ending of this episode fits as well, with the entire Possible family, along with Ron, and even Drakken and Shego enjoying Christmas together.
Shego is her usual Deadpan Snarker self, insisting on taking her Christmas vacation instead of helping Drakken, but is genuinely touched when she learns that Drakken, by way of a Christmas gift, had paid for her hotel accommodations. This discovery prompts her to contact Drakken, which is how she finds out he and Ron are missing, leading to her and Kim finding them.
One notable moment at the very end of the last episode, "Graduation". Drakken is getting an award for saving the world and clearly pleased, but unsure how he should react. He looks at the cheering crowd...then the sulking group of villains glaring at him...then finally to Shego, who is wearing a look we've never seen on her before; one that says as clear as day "I'm proud of you." Followed by their vine hug. One of the most heartwarming moments in an episode full of them.
Ron (as the Fearless Ferret) pushed the balloon-mounted stink bomb away from the Fearless Ferret convention when Kim was incapacitated:
A nice Kim/Ron moment from the first season (that also doubles as a Moment of Awesome for Kim) happened in the episode "Mind Games". In a "Freaky Friday" Flip plotline that had Kim and Ron switching bodies, Kim (as Ron) found herself facing the school bullies of Middleton High's D-Hall,note One of whom was actually voiced by Will Friedle, meaning he was basically bullying himself who had harassed Ron since kindergarten. This and other events caused Kim and Ron to each realize how hard the other has it. At the end of the episode (after Kim and Ron got their old bodies back), the D-Hall bullies approached Ron and gave back all the school lunch money they had taken from him since kindergarten.
Ron: What just happened? Kim: When I was still in your body, I went back to D-Hall. Gave some sensitivity training. No big.
The two full on Kim/Ron Kisses in the "Graduation" two part episode. The first when Kim reassures Ron that everything will be alright and the second when they are flying off to the stars together.
The second could count as a moment of awesome for Ron as he was the one who initiated, showing just how confident he became after getting control of his MMP.
The hug Kim/Ron share in the episode "Mathter and Fervent" after Ron is released from his anti-matter containment bubble.
Ron: Hey hey, alright! Whoa! Oh hey yeah, thatís nice. Kim: I was starting to think Iíd never get to do that again.
Ron and Kim's talk about life choices from the Season 4 episode "Mentor of Our Discontent".
Ron: Ok, I have no idea what just happened. But I am clearly not cut out to help people make life choices. Kim: Oh, I wouldn't be so sure. You helped me choose...you. Ron: Ok, that time I was a genius.
Ron suggesting that Kim should be the replacement model in "Trading Faces". Kim of course denies, saying she's no model...Ron retorts, "Why not? You're beautiful." Everyone with me now... D'awwwwww!
The best thing about that is the casual way he says it, as if it's far too obvious to argue with.
The episode "Clean Slate", which contains the first serious use of the "L word" (No, not thatone) after Kim regains her memories of her and Ron's relationship.
Kim: I remember that you're my boyfriend! And that I think I love you! Ron: For real? Kim: For real! (hug)
The end of the season one episode "Bueno Nacho" features Ron being the greatest friend in the world:
Kim: I know this is beyond shallow, but I saved the world and I'm still no closer to owning that Club Banana jacket! Ron: Maybe... maybe not. [pulls out gift box] Kim: [gasp] Ron?! Ron: It's no big deal. My Naco bonus was way bueno. Kim: You are too sweet! I love it! [giant hug]
In "A Sitch in Time" we see how Kim and Ron met in Kindergarten, with Ron actually defending Kim against some bullies (who turned out to be de-aged, time-traveling versions of Drakken, Monkey Fist and Duff Killigan, it's complicated). Kim at one point says, "You're weird, but I like you." And so begins a very beautiful friendship.
And it's made all the sweeter by the wistful look Present-Kim gives Pre-K Ron and her Pre-K self through the playground fence.
This scene actually gets a Meaningful Echo in the credits of a Season Four episode.
Kim: You're weird. Ron: Ah! K.P.! Kim: Shhh. I like weird.
Ron and Kim's goodbyes from "Sitch in Time", face it, every kid at some point had to go through with your BFF moving far away. *sniff*
Or Kim's line, said in the most heartbroken, yet sincerest way that makes you wanna dab your eyes with tissues.
Kim: Ron, I couldn't save the world without you.
Hana, Ron's adopted baby sister. The little girl was made of heartwarming moments whenever she was with Ron. The depth of which Ron cared about her was truly touching and his brief freak-out at realizing his baby sister was going to have to face an evil destroyer was an extreme tearjerker.
The total, all-encompassing love Kim's parents have for her; no matter how strict or overprotective they might be at times ("Black hole deep, Ronald"), it always comes from the heart. One notable scene in "A Sitch In Time" is when they drop her off at pre-K for the first time. They are so warm and supportive of their daughter, completely confident that she'll do fine: "Anything's possible for a Possible!"
A little moment at the start of "Mathter and Fervent", when Mr. Barkins gives the class the assignment of interviewing a hero in their own lives:
Ron: (confident) Hero, eh? Oh, the Ron-man has this one in the bag! Mr. Barkins: And no, you can't interview the person you're dating! Ron: (disappointed) Brutal.
Similar to the example from "Odds Man In" listed above, the line from "Graduation" where Ron tells Kim that the whole alien sitch makes him realize he can't live without her. I'm sorry, I need a minute...
Ron: If Kim's lost in the stars, I'm finding her.
From "Mad Dogs and Aliens"
Kim: Saving the world has other perks too. Ron: Such as? Kim: (smiles at him) Cuter boyfriends. Ron: Huh? Oh! Ah heh heh heh, a-booyah.
Also the ending where they walk off together holding hands.
In a weird way, it seemed kind of sweet how the villains seemed concerned for Ron in the episode "Grande Size Me," and they saw how fat and unhealthy Ron had become after eating nothing but food from Bueno Nacho for sometime—Monkey Fist even said to Ron, "You've really got to start taking better care of yourself."
In "Go Team Go!", the very fact Shego decides to help, and at the end lets Kim destroy the device that was giving her all the powers of the Team Go. Her brothers may be annoying, but Shego still loves them.
Dr. Drakken was actually not so harmless this episode and goes to save Shego in a giant flying robot.
Dr. D: (to Shego) You know, I do think of us as a kind of evil family. And families stick together! So if you need me— (warning shot) I'll be there for you! (later) Dr. D: Kim Possible's computer kid told me how you were at the mercy of a villain. Where is this "Aviarius"?!
In "Oh No! Yono!" when Monkey Fist is defeated, Kim is freed from the spell that turned her into stone. Ron notices, he looks overjoyed and runs to her. Not only that, but the two embrace and kiss. It's only for a few seconds since Hana jumps between them to hug Ron (they don't mind at all). Seeing how they usually get interrupted, it was nice that they got to kiss this time.