So long, neighbor

I live in one of the older, larger apartment complexes in town. Everybody who lives in Tampa has either lived there or known someone who has. When I moved in, some of the residents were pretty sketchy and it wasn't a really nice place but management has done a great job weeding out the scumbags and now it's pretty good. My neighbors are cool; sometimes they bring furniture outside, open their windows so you can hear music, fire up a barbecue grill and it turns into an impromptu block party, which is always a lot of fun. I like those people and they like me.
Of course, there has to be an exception.
The guy right next door (we're on the second floor and share a landing at the top of a set of stairs), for whatever reason, was not a fan of mine. I don't know why, I think I'm a good neighbor. I don't see how I could have possibly disturbed him. When I listen to music, I always use headphones and I haven't turned on my television in months. I do come and go at weird hours sometimes but I'm conscious of that and take extra care to not be disruptive. But when I'd see him on the stairs or at the mailbox or in the parking lot, I'd smile and say hello and if he replied at all, it would be a head shrug and a grunt.
No big deal. Sometimes people just don't get along with one another. Oh well. I don't need everybody to like me. It's no problem.
As I'd lay awake at night wondering why he didn't like me, I'd try to think of ways to change that. If he was walking his dog, I'd compliment him on how nice the dog looked. People love it when you engage them through their pets, right? Wrong. He would just kind of pull the leash away so I couldn't even pet the dog. If I was going down the stairs and he was coming up, I'd yield. He wouldn't even say thank you. Once we were in the laundry room together and I offered the use of the dryer my clothes had been that still had about 20 minutes on it. "No thanks".
Eventually, I gave up and started hating him too. Not actively. I mean, I still had to live next door to him. I mostly just stopped being friendly.
A couple of weeks ago, one of those portable storage pods were dropped off in the parking lot and I saw him carrying armfuls of stuff out to it. Oh good, he's moving out! Over the course of the weekend, he and some friends emptied his apartment. At one point, I heard him whining at his girlfriend for not doing something right as the two of them tried to haul a mattress down. "Typical", I thought. "He doesn't deserve her." I peaked out of the window to verify it. Yeah, even in sweaty, grubby moving clothes with her hair in a pony tail, she was way too hot for him. What a jerk.
Late Sunday afternoon, the activity had stopped and I needed to go out for something. I stopped at the door of his apartment and listened but didn't hear a sound. I peaked around the side and saw the patio was empty. Looking through the sliding glass door,I couldn't see the whole apartment but there were no lights on and nothing visible except bare walls and carpet. I stood in front of the door and flipped it off with both hands.

"Yeah bitch, now what? You're all moved out and if you had been nice to me, I probably would have helped you. I own a truck. I'm strong. I know how to carry a mattress. You didn't even have to be nice, just not be a dick. But guess what? Too late. You're gone. You can't glare at me across the parking lot and I never wanted to pet your dog anyway. I pet dogs all the time. What makes yours so special? Oh, is he a show dog that can't be handled by regular people? Well, fuck him and fuck you. Tonight, I'm going to cook collard greens and garlic while listening to the worst, loudest music possible. What do you think about that, huh? You don't like it but you can't do shit about it, can you? Nobody cares because you don't live here any more, do you? No, you don't."

As I was dry-humping the doorknob, I heard a click-click from inside. I stepped back quickly as my-soon-to-be-but-not-quite-yet-ex-neighbor opened the door.
"Hey. Do you need something?"
"Hey. Uh, no. No. I thought I saw you moving and wasn't sure if the apartment was empty or not."
"It is, but the dog run at the new place isn't finished so we're spending one more night here."
"Oh."
"That's why we're moving to a house. My dog, she's a rescue. She was abused pretty severely by her previous owners, and right now she's still not good around other people. She gets really nervous and tries to bite them."
"Oh."
"Yeah, this just wasn't a good environment for her to learn new habits. Too many people coming and going. She just couldn't calm down. I'm really sorry if she ever caused you any problems.
"Oh. Nope, no problems."
"I really appreciate you being a cool neighbor about that and never got a chance to tell you."
"Oh. Sure thing."
"Okay. Well, so long, neighbor." 
I waved by and turned to walk back into my apartment, now feeling absolutely awful. But then I remembered that I needed to go out. I turned around to go to the stairs just in time to see him flipping me off with both hands before closing his door.