I think people are so quick to judge here specifically because this is the internet, and we are able to pass our holier-than-thou judgements on people without anyone being able to see any of our own flaws. It's sad but true, and I'm certainly not innocent here. But I'm willing to admit I have flaws (PM me, I'll list them out for you

). And sure, maybe OP thought he had valid reason to do such a thing to his 3DS, but I don't think that's the issue at all.
People here are judging not so much his character, but a stupid decision; which I think we can all agree that it was a stupid decision. OP doesn't need us to tell him that though, I'm sure he knows that with all of his 3DS-missing heart. So why do we do it? We're self-justified on the internet. We feel like we have safety and power behind these screens. It's an interesting social phenomenon really, but I digress.
If it wasn't for the fact that OP had acted like "oh my 3DS is broken now, and I'm a victim" I wouldn't have posted anything. This is another social phenomenon that I find irritating; everyone's a victim. Sure, maybe OP has anger issues or has bipolar disorder, but that doesn't make stupid decisions any less stupid. I haven't checked recently, but I don't think anger issues OR bipolar disorder alone will ever get you out of the toilet if you happen to be on trial for murder (I know it's not nearly the same but stay with me). And I'd like to see you say "Oh judge, I killed my wife because I was having a bad day." Say hello to 25 to life. That's because despite any kind of emotional distress or instability, you are still a human being with the ability to make choices for yourself. I refuse to believe OP does not have the mental capacity to make these kinds of decisions, and if he doesn't, there are bigger issues here than a broken 3DS.
We as a society, we as a humanity have become this way though. Nothing is ever our fault. It's this disorder or it's this government or it's this environment I'm in. People used to rise above situations and make themselves better, but in this new era, humanity is dragging itself down into self pity and an inability to be self-sufficient, and I find it to be rather ridiculous. Anyway...
/rant