DHH talks about his personality in a very frank way. I feel the same. I'm not the sort to qualify for a job at Google. I don't think I really excel in a particular field, but I am very good at certain things. I never ever thought I'd be a programmer for a living, and I certainly don't think it's my forte.
I see it as a means to an end. I have a passion for creating cool things. If it means I concentrate on CSS, on Javascript, on C# on on Ruby then I'll do it. I wish I felt like I had time to create apps like Basecamp, or Google Maps, but I don't. So I create what I have time to. And in between doing that I think about the things I could do if I had time.
External deadlines aren't good.