I want scorn, mockery, and/or contempt, if possible.
Well you won't get any of that from me.
What you will get though is a recommendation to try to get out of your own head a bit. I know exactly what you're talking about concerning feeling either like you're worthless or will be perceived as such if you don't do A B C. It's really easy to get bogged down with that stuff. Most of us do at one point or another.
I've found that, despite the fact that it's far from obvious when you're embroiled in the mindset, is that one of the main reasons you're depressed and feel bad about yourself is because you're constantly obsessing over all the things you should be doing all the time. It drags you down, makes you feel like you've got a thousand things going on in your head all the time, like steam is going to come out your ears.
It's one of those self-reinforcing cycle things: you haven't accomplished something you want to accomplish, therefore you worry and stress over it, which makes it harder to get motivated to accomplish stuff, which makes you stress and worry etc. until one day you find yourself bogged down in the proverbial muck, and feeling like absolute crap.
Take this as a start: after reading your post, I'm not judging you for anything, nor do I think you're a parasite or anything else, and neither should you. You're a perfectly legitimate human being like everyone else.
If given the chance to take a look at some stuff in my life, you'd find lots of things I screwed up, didn't try hard enough with etc. The same is true for anyone else you meet. The expression "nobody's perfect" is such an understatement it tends to undermine the very point it's trying to convey.
I read that Cracked article awhile back when it first came out, and I think it has some really, really good advice. Though it can hit you like a ton 'o' bricks, and be misinterpreted if you're already depressed.
Take a breath, relax and calm down. What do you want to do. what do you want your life to look like. How do you want to make the world better? figure it out, and go do it. My recommendation would be to start with the artwork you said you never posted. Post it, let people enjoy it.
Always be doing something, anything to make yourself just a little bit better. Health, skills, knowledge, being a better friend etc. The list goes on. And always be doing something, anything, that benefits people, no matter how small.
Now mind you I've got a loooong way to go to properly follow my own advice, but from what little ways I've gotten along this route, it's like I'm living again for the first time in many years.
For a bit of clarity, I'm 22, and I've had serious depression and similar issues myself, for various reasons. It will get better, I promise you, and it starts by shaking off the chaos going on in your head, the sense of crushing obligation, of worthlessness, and getting up and doing something you can be proud of, and going full steam ahead from there.
Hell hang out some with the WMM community here, learn about hypnosis and maybe learn to trance(hypnosis is real, scientifically verified and far from pointless. The previous posters here really explained it very well, I think)