After Steve and Myra survive a near-death experience, he realizes how much he really cares for her and decides to give up chasing Laura (for now, anyway) and let himself love Myra. He then gives her his Science Club Pin, and they kiss.
And the reason why they're in Russia and he isn't? In a previous season they abandoned him for a research project. That episode ends with the Winslows agreeing to look after him while they're gone.
Eddie letting Waldo know, in no uncertain terms, that they'll always be best pals no matter where they go after high school.
Waldo discovering that he is an excellent chef, which gives him a chance to be more than just the neighborhood idiot when he goes off to culinary school.
When Maxine mistakenly thinks that Waldo is cheating on her with two other girls (not knowing that Eddie was responsible), the girls are so moved by Waldo's tears, not to mention disgusted by Eddie's attitude, that they go straight to Maxine and explain the truth.
Eddie accidentally throws one of Laura's cherished dolls away, so Steve spends all of Christmas Eve looking for it at the dump. He finds it with the help of a dog.
Carl shows up for Steve at school when his own dad wouldn't, and Steve, in surprise, responds with "Big guy!" and glomps him.
Steve starts a drive to save a classmate of his who has leukemia, despite the fact that the guy is always bullying Steve. At the end, the classmate thanks Steve and offers to buy him lunch.
In one episode, Steve plays poker with Carl and his police pals. He initially loses badly to Murtaugh and didn't know they were playing for keeps. Carl gives Steve his own money to make him happy, but the nerd decides to get back in the game and get back at Murtaugh. He wins, even taking Murtaugh's prized watch in the process, but he opts to give it back.
Steve: I play for fun. Murtaugh: You're all right, kid. [salutes him]
At the end of the episode, Carl and Steve opt to cut the cards for a little bet. Steve has to stay away for six months if Carl wins, but can come over whenever he wants if he wins. Steve draws a three. Carl then draws, and he (and the audience, but not Steve) sees that he's gotten a face card and, without any kind of anger or disappointment in his voice-
Carl: Deuce. I lose.
In the Gun Safety episode Steve despite normally being a coward, has the guts to stay by Laura's side so she didn't have to go to school alone when a bully threatened her with a gun the day before.
Upset, 3J hides out in the Winslows' attic. When they find 3J, they announce that they want to be his foster parents, and will speak with his case manager. Before he goes to share Richie's room, he hugs Carl and Harriette.
In a later episode, 3J is suspiciously doing a lot of extra chores (poorly) around the Winslow home. Harriette asks him about it, and he lets it slip he's worried he'll be sent back to the child shelter as he had been numerous times before. Harriette reassures him he's a part of the family.
In "Presumed Urkel", Steve faces expulsion when a science lab he was working in is blown up. Who defends him? Laura does, who has a lot of reason to dislike Steve. And Carl, who has dealt with Steve's mishaps more than anyone testifies in court, he tries to downplay the damage and also points out that while Steve has done damage, he's never lied, so if says he is innocent, he is innocent.
In the last season, the episode when Eddie decides to become a cop. Earlier in the episode, Carl was less than thrilled to hear this, and an argument ensued. The Heartwarming Moment comes when Carl takes Eddie to a bar, points out former cops who have been maimed in the line of duty, and asks Eddie whether he still wants to be a cop. When Eddie says yes, Carl tells him to stand up and introduces him as the newest member of the force, to the applause of everyone present. Doubles as a Moment of Awesome.
During the episode "Daddy's Little Girl," Laura develops a crush on Carl's attractive new partner Mike. Carl doesn't handle it well, and embarrasses his daughter in front of Mike. He later comes to Laura's room to make up, and a heartwarming speech ensues, complete with Laura's old Companion Cube Humphrey Bear-gart, which Carl won for her at the county fair when she was six.
Richie is pretty depressed in "Deck the Malls" when he learns Rachel won't be able to fly in from Detroit for Christmas. Eddie takes it upon himself to drive all night so she can be home with everyone else.
Eddie: It wouldn't be Christmas if the whole family wasn't here, now would it?
Steve got Carl and Harriette a portrait of Eddie and Laura.
Carl: Well, you know something, Steve? There's only one thing wrong with this photograph. Steve: What's that? Carl: You're not in it.
In "Best Friends," Eddie hires Waldo to work at Mighty Weenie. Various mishaps ensue, and it looks like Waldo will have to be fired. Eddie isn't sure what to do, but after talking to Carl, he decides to play to Waldo's strengths: cooking. Things really turn around and Waldo later gives Eddie a Man Hug.
Eddie: What was that for? Waldo: For not firing me. I was messin' up real bad, but you stood by me and found me a job I'm real good at. You're the best friend a guy could ever have, and I love you, buddy. Eddie: Well, you've always been a great friend to me. The least I could do is be one back.