α) It's better to have tried and failed than never to have tried at all.
β) It's okay to fail as long as you tried as hard as possibly could. (I don't claim I did!)
γ) Procrastination is okay, but is has to be limited and most importantly: the desire to procrastinate a lot has to be taken as a sign that something is wrong with the work and this has to be fixed!
δ) Everybody has their limits in what they can achieve. The question is not how big or small your limits are, but how you can expand them – and the latter is usually done by overcoming bad habits.
ε) Everybody has to live with the talent they have – the only thing we can change are our attitudes and our habits.
ζ) If you are stuck on a small problem, you might just take a break (procrastinate, yay!) and try again later.
η) But if you are stuck on a bigger problem, procrastination doesn't help. First of all, you need to embrace the new problem as a challenge. Then you get out your toolbox to attack it systematically.
If something seems harder than it should be, that doesn't necessarily mean, you're on the wrong track. If in doubt, check back with someone to confirm your approach. Doubting which way to go is a bad thing likely to stop you, or waste a lot of time.
For me it seems the best way to get out of a circle of doubt is to talk through all the options with someone on a technical level. In other words: get help.
Before I came to Toronto, I never had anybody interested and knowledgeable in my specific field of research. And in Toronto I think I didn't get as much advice from my advisor as I should have.
While I don't want to whine about all the things I've done wrong in grad school, I would really like to draw some lessons, so I take something useful away from my experience. But how would this experience be useful for me later? I clearly do not want an academic career and not another try at a PhD either! But I seem to be attracted by small challenges and I might encounter those at work or other places and it'd be good if I could attack those without biting my teeth out again. Since I don't seem to like mixing work and challenges, I will have Wikipedia and Opensource projects as my playground to achieve great things. Even in the few Opensource programs that I am using everyday, there's quite a few long-standing bugs and missing features that need fixing – since nobody done that yet, I suppose it ain't easy – thus a possible small challenge for me.
So my hope is that despite not having achieved my research goal, I can somehow make use of he experience later. Whether my research work is carried on by others or not, is out of my control. But my experience belongs to me and I should make the very best use of it.
People see me very sad when I talk about my failure in research and thus my failure in Toronto. But this disappointment with research doesn't mean that I didn't have a great time here. I met great people, I had great sails and great bike rides. I took interesting classes (favorites: computational linguistics with Gerald Penn, and network architectures with Yashar Ganjali) and attended inspiring talks (favorites: Louis von Ahn about human computation, Alan Kay about wholesome software architecture, as I call it; and special price for best presentation paired with most appalling content: Damian Convey on some Perl stuff).
Despite this, I am still somewhat upset because life is not about fun alone. And the main reason I came here –for what it's worth– was my research project. And part of why I am leaving now is that that's what most students do after graduating. TO might be a great place to live (that is, to sail), but for me it's first of all the place of my research project which is now about to end.