I get lost in my own house - and it's not even a big house.
In mapping, where I have no sense of direction, my needs are likely to coincide with the needs of lots of people.
I still run into people who loved Wave - who thought it was the best ever and can't believe that Google canceled it. And whenever that happens, it's like I'm looking at a mirror-image of myself: someone who is similar to myself in skill, experience, and profession. And that's just not a mass market.
So, it was a tough decision to leave Facebook, but it was definitely the right decision. I haven't regretted it at all.