Also Real Life: John Heard was vocally unhappy about working on the first film, considering the role beneath him and believing the film would flop. Upon seeing the finished product, he profusely apologized to Chris Columbus, going so far as to do it on camera during shooting for the sequel.
Gus Polinski offering Kate a lift after discovering that she needs to get to Chicago.
The whole scene where Kevin meets the guy dressed as Santa Claus. The guy is tired, frustrated, and just trying to get home when his car won't start, but he still takes the time to listen to this kid and try to be Santa to him.
When Kevin asks for his family back, he names his mother, father, brothers and sisters, Aunt Leslie, cousins, and if Santa has time, Uncle Frank. Frank may be a massive Jerkass to Kevin, but he still has a place in Kevin's heart.
Santa giving Kevin some Tic Tacs because he's out of candy canes is incredibly sweet, since he believes "Everyone who sees Santa should get a little something."
Kevin getting an entire cheese pizza all to himself after Buzz eating it all just to spite him at the beginning of the movie.
Harry and Marv slamming on the breaks and shouting to stop, respectively, when Kevin wanders into their car's path. They may be burglars but they don't want to kill someone. (Yet, anyway.)
After that, Harry warns Kevin to be more careful when he crosses the street in a crude but still worried way. Marv to ease things up warns Kevin in a more affably tone that "Santy doesn't visit funeral homes". Once Harry cools down a bit, he decides to brighten things up by gently wishing the kid a Merry Christmas.
Kevin talking to Old Man Marley in church, discovering he's actually quite a nice man despite all the scary rumors.
Kevin's mother Kate being comforted by the Polka King after calling herself a terrible mother.
Kevin and his mother reuniting at the end of the first film. Made even better when the rest of the family walks through the door seconds later.
Old Man Marley reconciling with his son and reuniting with his family, which Kevin witnesses.
Add in Marley giving Kevin a thankful wave, as Kevin was the one to suggest that Marley actually call his son and try to make amends.
Buzz praising Kevin for not burning the house down while they were gone.
A few Deleted Scenes show that, despite being jerks to him in the beginning of the film, Megan, Linnie, and Jeff do love Kevin and spend most of their stay in Paris worrying about him. In the Paris scene, Megan is clearly worried about Kevin and voicing her concerns to Buzz, who just plain doesn't care.
In another deleted scene, Linnie finds that Peter is unable to sleep since he too is worried about Kevin. They then share a heartfelt moment on why they both think togetherness is so important at Christmastime.
In another Deleted Scene, we see Harry and Marv joking around in the van. This suggests that despite their occasional bickering, they appear to have a genuine Villainous Friendship.
Home Alone 2
Buzz's heartfelt speech/apology to Kevin. He's actually kind of a nice kid, when not acting like a total dick.
The first time and the second time we hear "Christmas Star". The first time was with Kevin missing his family once again while looking at a view of New York at night. What adds to the heartwarming is that he says goodnight to his mother, while at the same time in the Florida Resort Kate is saying goodnight to Kevin. The second time was before he decides to deal with Harry and Marv. He makes a stop at the Beth Israel Hospital Children's wing. A sick kid looking out the window waves to Kevin, who waves back. This motivates him to stop Harry and Marv from robbing the toy store, since the proceeds are supposed to go the hospital.
Buzz giving Kevin the first present to open on Christmas morning.
Uncle Frank cheering for Kevin shortly afterward. Nice to see after he spent the first two movies being a complete ass to him.
Although he's giving away his father's money, Kevin donating money to the hospital was a sweet gesture.
Kevin thanking the Pigeon Lady for saving his life, followed by the lady blowing a kiss to him.
When Kate realizes where Kevin could be found in New York, she asks the cop if he could take her there using his patrol car. The cop in question doesn't even hesitate.
Kevin giving the second turtledove ornament to the Pigeon Lady.
Kevin's relationship with the Pigeon Lady is this, being he convinces her to not be so closed up, telling her that you're going to be hurt sooner or later, but shows you're alive. Especially heartwarming in the end when he gives her a turtle dove and says they'll be friends forever. Daaaw.
Harry's promise to take Marv to the Central Park Zoo when they have time to kill before the heist. Nice to see him doing something nice for what we might assume is his only friend.
How about the fact that Kevin willingly chooses to spend "another Christmas in the trenches"? In the first film, he was defending his home from Harry and Marv because he didn't have much other options. This time, he willingly puts himself in harms way to get Marv and Harry caught because they're robbing money from a toy store that was meant to go to a children's hospital. Kevin puts himself in willing danger for a selfless cause for those who are less fortunate than he is.
Home Alone 3
Alex getting rewarded for his role in catching the gang, as well as getting respect from his family for it (in contrast to Kevin's, who didn't know about Harry and Marv), who don't even seem to care too much about any of the damage his traps caused to the house (no doubt because of said reward).
Alex's older siblings seem to take as much joy in tormenting him as Kevin's did, but the instant it seems like he's in real danger they close ranks and show they are firmly on the side of their younger brother. In the end, they seem more happy about the fact that Alex is alive and well than any incidental damage done to the house.
When going to another house for safety, Alex encounters Mrs. Hess tied up in the garage and left to freeze to death. He then proceeds to close the door and place his own jacket over her, even though it's not too much bigger than a large towel. After untying her and getting her to safety, he then says to her, "It's really cold out there. You're a tough ol' bird." She then replies back, "And you are a sweet young man." It's sweet that he was able to not only save her but for her to be thankful for him, especially since she felt rightful resentment over being asked to regularly babysit by a family who doesn't even otherwise invite her into their home. Furthermore, when the cops do arrive, he asks them to help her as she was still ill from the open door and the film ends with her and the family sitting around having cocoa and thanking Alex.
Home Alone 4: Taking Back The House
Peter and Kate hugging each other when they get back together at the end of the movie.
Home Alone: The Holiday Heist
Alexis and Finn hugging once they manage to defeat the villains.