Dig deeper, Sam. Achievement-oriented people are given to depression both when they fail and when they succeed. If your identity is tied up in your work, then you feel bad about yourself when work isn't going well. That's obvious, and that's the message of this blog post. The implicit message is that you're depressed because you're not succeeding, so get your shit together and succeed and be happy like everyone else.…
The reason why that is, is because even though I never do things just because others want me to do them[2], I am still very much driven by success and achievement. Not because society compels me to achieve, but because there is an internal drive that just will not shut up. Kundera explained it well in Lightness of Being - there is an inner voice that says you have to. You must. Even though you know full well following this path does not make you happy, moving away from that voice makes you even more miserable. Just because you're not following your talents/gifts[3].
When it comes to success vs. failure. Succeeding brings with it doubts in terms of whether you're succeeding rapidly enough, whether there's more you could be doing, whether your goals are high enough. When you're failing, you're failing and failing never feels good.
And there's nothing that even compares to the emptiness that comes when you achieve a goal. It's soul crushing. All that work and now you're done ... what can you possibly do with your life now? What else is there? What's the next step? If I could achieve this goal, was it even lofty enough?
In the end, I've learned to simply manage my depression and live with it.
[1] I think I fall in the camp, it's hard to say, I've never achieved much that the outside world would laud me for, but I tend to behave like achievers do and have been obsessed with success/achievement ever since I can remember
[2] ask anyone, I am impossible to motivate externally. Beating me with a stick until I do what you ask would probably work eventually, but that's a tad severe.
[3] great Oglaf comic on the topic of talents/gifts wanting to be used: http://oglaf.com/gifted/