1. Didn’t tell anyone he and Nancy slept together.

When she admitted to feeling like everyone was staring at her as if they knew, Steve assured her that he didn't tell anyone. It's implied by Nancy that he's had several superficial and sexual relationships with girls in the past, but for him, Nancy was different, and he respected her enough to not go blabbing about their night together. He wasn't one of those dudes who would brag about her as if she was merely another notch in his belt.

2. Took care of his friends, even though they sucked.

Almost subconsciously, he gives Tommy his applesauce and wordlessly forks over his meatloaf to Carol when Tommy destroys hers during some "comedy" bit. The Mom Friend that emerged in season two had been there all along. He's naturally nurturing.

3. Attempted to help Nancy figure out what happened to Barb.

When Nancy was worried, he sought to calm her fears by offering logical alternatives to why she wasn't at school. Maybe she was just skipping. And when Tommy rudely told Nancy that he had "seriously no idea" who she was talking about, Steve kept him in line and got him to answer honestly. Of course, this attempt at helping ended when something really could have happened to Barb and he was more concerned about how his jerk of a dad would react to the small party Steve threw in his absence than her well-being.

4. Protected his girlfriend when some guy took photos of her half-naked without her consent.

He definitely went too far by breaking Jonathan's camera, and that's inexcusable. But from his perspective, he was protecting Nancy. He found out that this guy he's probably never talked to took photos of him and his friends without their knowledge—including shots of Nancy in her underwear. Jonathan seemed like a stalker and a pervert to Steve, and he was taking what he deemed to be the necessary steps at getting the guy to stop. Misguided, but his intentions were good.

If I was in his position, and someone took stalker-ish photos of my friends and me, I'd rip up the photos, too. What Jonathan did was creepy and out of line. Steve overreacted, but he was trying to protect his girlfriend from who he thought was a pervert.

5. Recognized he was being a jerk about Barb’s disappearance and apologized.

After he and Nancy fought about his reaction to something possibly happening to Barb, Steve recognized how he messed up and apologized to her, assuring her he realized how much of a jerk he had been. He admits that he had gotten trouble—the thing he had been so worried about—but he passed it off as no big deal. (Though if his dad is as awful as Steve has implied, then I'm sure it was very much a big deal in his house.)

Plus, we got his adorkable rendition of "Old Time Rock and Roll" with the baseball bat as his improvised microphone.

6. Was in tune with Nancy’s behavior enough to notice she was upset and went to check on her.

He could tell by how Nancy was acting that there was something wrong, and he was worried about her, so naturally, he went to check on her...and found her in the arms of another guy (specifically, the guy who took half-naked photos of her without her consent). Then he messed that up, too. Sigh. That poor, idiot son of mine. The point is that he cared about her, okay? There was some seed of goodness in him that was twisted by the bad influences in his life.

7. Called out his friends for being awful and broke ties with them.

He finally recognized how truly terrible Tommy and Carol were, and he told them off. They kept talking about how creepy Jonathan was and insinuating he was sleeping with Nancy, and Steve snapped. He stood up for Nancy and told Tommy he shouldn't have spray painted what he did and regretted not shoving the bottle of spray paint down Tommy's throat. The fight escalated, and Tommy seemed ready and capable of giving Steve his second beating of the day, but instead let Steve go. Steve drove off, leaving his "friends" behind for good.

8. Cleaned off the movie theater sign.

He drove from Tommy and Carol and to the movie theater, wanting to erase all evidence of his lowest point. Who knows how long he stood up there, scrubbing those hateful words away.

9. Went to Jonathan’s house FIRST to apologize for his behavior.

The next stop on his apology tour, before facing Nancy again, was Jonathan's. He knew he had gone too far, that he had messed up, and he wanted to make things right with Jonathan. The fact that he didn't go to Nancy first and then to Jonathan, most likely only apologizing because it would be what Nancy wanted, shows how his heart was in the right place. He wasn't trying to make things right with Jonathan in order to win Nancy back. He just wanted to do the right thing.

10. Saw Nancy’s bleeding hand and immediately sprang into Protective Mode™.

"Wait a sec. Did he do this to you?" The guy who took photos of you without your consent? The guy I taunted and then beat the living crap out of me? Steve had absolutely zero idea as to what was going on, but if Nancy was in trouble, he wanted to protect her.

11. Had the chance to leave the Byers’ home and save himself, and instead he chose to go back in and fight the Demogorgon.

This was the moment that showed he had truly changed, the crux of his redemption. He was clearly scared out of his mind, but instead of being a coward and running away, he stayed and fought with Jonathan and Nancy against some impossible creature. (And did so with style. THAT BAT TWIRL THOUGH.)

12. Bought Jonathan a new camera to replace the one he broke.

Okay, so technically it's not canon that Steve is the one who gave Jonathan the camera, but hear me out. Nancy tells Jonathan that it's "not really a present," because it's not; it's replacing what Steve destroyed. And Steve clearly knew about the gift, hence checking with Nancy to see if she gave it to Jonathan. There's always the possibility that the camera was just from Nancy, and so the writers including that line was mean to show he just...knew about it?

To me, the more likely scenario is that he—possibly with the help of Nancy, possibly not—bought the camera for Jonathan as an apology or peace offering or attempt to make up for what he'd done. But becase their relationship was still too tense, Steve figured Jonathan would be more likely to accept the gift if it was given to him by someone he was closer to, like Nancy.

So when Nancy said that yes, she gave it to him, Steve settled in with a smile, because it was Christmas and he had the only girl he'd ever really cared about before in his arms—and he felt like he was finally becoming the kind of good man that she deserved.

(Also, the fact that he was spending Christmas with the Wheelers, complete with a dorky holiday sweater. That's not even an argument for him being a good guy. It's just adorable.)