Wow, are you me?
I suspect that if I were even a little dumber (and mind you: I'm bright, but not that bright, ya know?) I'd probably be homeless instead of doing pretty damn well as a developer. Then again, maybe I'd be better motivated if couldn't achieve 7-8/10 results on a 5/10 level of effort. Only trouble is when I need to hit 9 or 10 on a deadline...
Weird thing is, I have a phenomenal work ethic on projects that involve physical labor, and not just the purely mindless kind, provided I'm not the only one working on the project—if it's solely up to me to start it and follow through on my own, it won't happen until I have one of my "I feel like I can conquer the world!" days when I inexplicably feel full of energy and confidence and motivation, and I only get those a handful of times a year. Anyway, point is, that tells me it's not some pervasive defect in my very being. I can have a great work ethic, without even trying, really, under the right circumstances, and I feel good when I do—I don't work grudgingly in those cases.
Curious if you've observed similar things in yourself.
As for modifying my behavior and fighting laziness: I've found I've gotten a bit better at this naturally as I've grown older (now early 30s) and sometimes actually win the battle of wills with myself, but my main insight has been that if I'm serious about something I must engineer my environment for success. Sorry to say it, but if other things are taking up time you want to spend on something else, your best solution may be to mercilessly eliminate distractions as you find them while also making it easier to choose to do the things you wish you would do by putting the tools and materials you need (if any) somewhere convenient. Like, sell-your-gaming-computer/consoles—pretty extreme. Or at least put them somewhere really out of the way. Maybe find some way to unplug it all and stick it in a closet, and always put it back when you're done.
It's tough, but it works.
Given this discovery, I dream of a world where I can live in one house engineered for learning and productivity most of the time and another with all the distractions I enjoy the rest of the time. If only houses weren't so expensive, heh.
Short of that, you can commit to only engaging in your distractions in the best possible way. "I can watch movies or TV or play video games, but only ones of high artistic merit or great significance". "If I want to switch windows away from work and read crap on my laptop, that 'crap' must be a classic from Project Gutenberg." "If I pull out my phone for no immediate purpose, the only thing I can do is run through flash cards, or Duolingo". That kind of thing. It's usually harder (though far from impossible) to over indulge with restrictions like that in place, provided you can stick to it—such media is chewier, less addictive. Doesn't make you feel as bad afterward. Steak and asparagus versus cotton candy.
For my part, HN will probably have to go soon, and I may start unplugging my Internet a few days a week. I'll have to experiment with the latter, we'll see how it goes.