- "Doug's Fair Lady": Patti and Doug are sharing the same cart on the "fastest ferris wheel" at the fair. Once the ride stops, Patti asks Doug if she can help him out of the cart, and takes his hand. As it's all happening, the fireworks go off.
Patti: Wow Doug, isn't this amazing?
Doug: Yes. It really is.
- "Doug's Fat Cat" is one of the most heartwarming episodes of the whole series. Roger asks Doug to take care of his pet cat, Stinky, while he and his mom go to a monster truck show. Despite picking on him all the time, Roger trusts Doug.
- When Roger and his mom drive up, Roger's mom and Doug share a polite, warm greeting. Roger may be a bully, but his mom is a very nice lady.
- Right before he and his mom drive off, Roger sincerely tells Doug that he's counting on him. Even Doug is taken aback by how much Roger cares for his cat.
- Roger and his mom immediately come to the vet after Doug tells them that Stinky is sick. Roger had said earlier that he'd been looking forward to the show all year, but he didn't need to think twice about leaving to make sure his cat was okay.
- When Roger arrives at the vet, Doug is terrified that Roger is going to be furious at him, but instead Roger just asks him what's wrong with his cat, even collapsing to his knees and crying.
- As it turns out, Stinky is female and her being "sick" was actually a sign that she was pregnant: she ends up giving birth to a litter of kittens. The pizza and ice cream that Doug gave Stinky was just what the doctor ordered.
- The end of the episode shows Roger happily playing with his cat's kittens. One of the kittens snuggles up to Doug and even Porkchop is seen happily playing with them.
- Any of the times that Roger and Doug end up getting along is always pretty heartwarming whether it's Doug making a slice of banana pizza for Roger since the class ate it all before he could get a slice ("Doug's Cookin'"), Roger organizing a surprise party to celebrate Doug's first year in Bluffington ("Doug v.s. the Klotzoid Zombies"), or their chat in "Doug Graduates" when they bond over their shared fear of moving on to junior high/middle school. Despite the antagonistic attitude Doug has toward Roger, he does still consider him a friend of sorts.
- While "Doug's in the Money" was somewhat bad (Doug returns an envelope full of hundreds of dollars out of the kindess in his heart, only to receive a pack of gum, and losing respect from some of the kid characters), the ending was pretty sweet. When Doug is walking away, his sister Judy drives up to him and offers to take him to the Honker Burger, on her. Considering some of the mean things she's done to him, this was a heartwarming moment between them. It's also a good example of the kind of person that Doug is. The money in question was in an envelope that Doug turned into the police. After 30 days, no one had claimed it, which meant, legally, the money belonged to Doug. When he saw the rightful owner (an old lady) on the news, even though he was now under no obligation to do so, Doug still returned the money.
- Note that during the reaction shot of getting a pack of gum for his efforts and being heckled by Roger, Doug is smiling nonchalantly. He didn't care about getting praise or a reward, he just wanted a clean conscience.
- In one of the early episodes Judy is supposed to perform at Doug's school with Doug himself forced to introduce her. Knowing how weird she is, Doug tries everything he can to get her to change her mind until he sees her backstage as he was trying to hide. She's distraught because they can't find Doug and nervous that she won't do well until Doug comes out of hiding and proudly introduces his sister.
- "Doug Rocks the House": After Doug knocks down Patti's old house with a rock (to impress Roger and his gang), Patti gets mad at him. Doug doesn't understand why, until he finds a picture of her and her friends at her old house. Skeeter tells him that she lived there until her mom died, so Doug goes to the area where her house was knocked down (it was actually in a construction area), and finds a doorknob, thinking she might remember her old house from it. When he brings it over, Patti tells him it was from her next door neighbor's house, but tells him she'll keep it. Doug at first says she's only keeping it to remind her about how stupid he is, but then she hugs him and tells him it'll remind her of how sweet he is.
- "Someone Like Me", a song that Doug sang in the Disney World stage show (and it also shows up in the end credits for The Movie). The beautiful lyrics are really heartwarming.
- A subplot of "Doug's Midnight Kiss" (a New Year's episode) involves Judy being annoyed by all the New Year's Eve celebration, brushing it off as "bourgeoisie" and "plebeian", and spending most of the episode trying to avoid it. But near the end, she gives up and sits with her parents to watch a movie, and they end up falling asleep on each side of her. Then, as she watches the ball drop to ring in the new year, Judy kisses her sleeping parents on their foreheads, saying "Happy new year, Mom. Happy new year, Dad", in the sweetest, most genuinely loving tone imaginable. And to top it off, she then blows one of the noisemakers that previously irritated her so much.
- "Judy's Big Admission" has Doug going to stay for a weekend with Judy at her prospective college, Vole, where she tries to get admitted. The episode is full of heartwarming moments between Judy and Doug:
Doug: Forget it, Judy, I don't have any talent.
- After Judy's audition performance is cut off after three lines (because the judges were so tired of watching audition after audition), she's heartbroken at the fact that she probably won't be accepted, and Doug hugs and comforts her.
- When Doug finds out that he lost a comic book art contest that he entered, Judy raises his spirits with a speech that uses her own experience with being rejected as an example. This bit really stands out:
Judy: Well, not talent like mine, perhaps... but you do have talent, Doug.
Doug: Yeah, right.
Judy: Listen, Doug - it's not important what other people think about your talent. Even when it seems that no one else believes in you... you have to believe in yourself.
- After Judy admits to the judges that she's been passing off Doug's drawings as her own, Doug convinces the judges to give her another chance, pointing out that he couldn't draw the pictures that he did if they only let him draw three lines. And when Judy does get another chance, she impresses the judges and is accepted - and shows Doug her gratitude by blowing him a kiss.
- If you were a kid that was chosen as Quailkid in Doug Live! at Disney World, this was what probably happened to you (as well as a Moment of Awesome) when you were on stage with your childhood hero. This also must've happened when you got your picture taken with Doug and Patti outside the theater.
- During one of the Nick episodes, Doug's aunt, who doesn't really realize he's not 5 anymore and works at a TV station, puts Doug on a really humiliating cowboy show that Roger happens to catch. Roger of course take the opportunity to torment Doug.. until Doug's aunt reveals Roger was also on the show last year to his humiliation. So the two boys decide to have a viewing party of the tapes they received... watching them burn and generally enjoying each other's company. Given that Roger spends most of his Nick screen time stalking and tormenting Doug, it's an oddly sweet moment.
- Doug and Patti dancing in The Movie.
- Doug and Roger's heart-to-heart in their graduation episode. Roger, of all people, is actually afraid to move forward, and in helping him Doug realizes what's been making him feel so down about it.
- Chad's talk with Patti in "Patti's Dad Dilemma". Instead of getting mad at her for being nasty to Miss Kristal, he comforts her, telling her that nobody will ever replace her mother, and that while he plans to keep seeing Miss Kristal, he wants Patti to feel happy about it.
- In "Doug's Worst Nightmare", seeing Roger so uncharacteristically peppy and friendly after falling for Judy.
- At the end of "Doug vs. the Klotzoid Zombies", Doug works up the courage to go over to Roger's and asks him why Roger excluded him from whatever activities Roger's been up to. Upon entering Roger's trailer, Doug is very surprised to find that all of his friends (including Roger, although he tries to play it off) planned a surprise party to celebrate the 1 year anniversary of Doug moving into Bluffington.
- "Doug's Christmas Story" is one huge example. Considering the Christmas time frame, it had the potential to be a Crowning Moment of Heartwarming by default. Of course, this gets subverted when Porkchop is accused of attacking Beebee and taken to the pound (with the Blufffs threatening to have him put to sleep, no less). But the lengths Doug goes to in order to get his dog back, plus the Rousing Speech he makes in the courtroom, double subvert the trope and push the episode right back into heartwarming territory.
- Of particular note is a brief flashback showing the Christmas that Doug received Porkchop.
- In "Doug and Patti P.I.", after Doug realizes that Roger was the one who stole the bumpers because Roger was sad that his dad couldn't be with him for the wheel-barrel race, he doesn't get mad at Roger or hold it against him. Instead, Doug asks Mr. Dink to participate in the race with Roger as Roger's stand-in 'dad'.
- In "Doug's Mail Order Mania", Doug enters a contest that lured him in with a sweet grand prize, but every round requires an increasingly-high amount of money to continue, to the point where he very nearly spends his college savings bond on it. Meanwhile, Doug is also making a sculpture of Porkchop to enter an unrelated art competition, but all his efforts go into the first contest even though it's quite obviously a scam. Eventually he gives up and is bummed out about it, but then he receives a letter in the mail saying his sculpture came in third place in the art contest, which confuses him since he had forgotten all about it. That's when Judy reveals that she submitted the sculpture for him and reminds him not to lose sight of his talents.
- The series finale "Doug's Marriage Madness" is full of heartwarming moments, which makes this the perfect way to end the series.
- Patti's friends have joined together to be bridesmaids and groomsmen in the wedding of her father Chad to Ms. Kristal.
- Everyone has tried hard for the wedding to be perfect (so hard that they end up thinking more about themselves than the bride and groom)
- When Principal White faints, everyone starts fighting, and Doug saves the day by stepping up and reminding them the real reason they came to the wedding. He tells everyone about the changes he's noticed and that the only thing that never changed was what good friends everyone is. Since there's nobody to perform the ceremony, everyone joins in to perform the ceremony. After the wedding ring falls out of Doug's shoe, Chad slips it on Miss Kristal's finger, and the bride and groom kiss as everyone cheers for them, and Patti sheds a tear of joy.
- After the ceremony, when Judy drives off to college, Doug confesses to the viewers that despite their differences, he was going to miss Judy. Right after that, Dirtbike says her first word: "Doug", much to her brother's joy and surprise.
- Al and Moo Sleech run into Miss Kristal's nieces and find themselves with girlfriends.
- Patti puts her arms around Doug's neck as she thanks him for saving her father and stepmother's wedding. This gets no less heartwarming when she asks Doug on a date-date to the upcoming Summer Harvest Moon Festival.
- When Doug's journal is full, Porkchop gives him an early birthday gift:a brand new journal.
- Doug ends the series by telling the viewers, "So long, everybody. It's been fun. Your friend forever, Doug".
- Word of God says that, while Doug and Patti don't get together in the end, Doug will at some point have an unnamed female friend that he bares his soul to about Patti — and in the end, realize that she's the one.