Paul Graham is notorious for saying, "Just build what people want!"
Well, do you want what I built?
Recently, I built something called ThinkSuite.
http://synaptitude.me/#ThinkSuite
It is an application that tracks mood and focus while you complete tasks, enabling users to view a log of what user were most interested, how tired they were, where they focused, etc.
After it tracks users, it can (though it has not been fully implemented) provide neurofeedback therapy to improve focus and mood, as well as identify users with mental illnesses. This is often used to treat ADHD, anxiety, depression, and epilepsy, it works similar to meditation or a workout trainer for your brain.
We even applied to YC with the idea:
http://synaptitude.me/blog/our-ycombinator-s15-application/
Regardless of our YC application, we plan to continue development, because... Hell, I want to use it. Plus, Paul told me not to give up (lol):
> So I’ll tell you now: bad shit is coming. It always is in a startup. The odds of getting from launch to liquidity without some kind of disaster happening are one in a thousand. So don’t get demoralized. When the disaster strikes, just say to yourself, ok, this was what Paul was talking about. What did he say to do? Oh, yeah. Don’t give up.
- Paul Graham, How Not to Die
So, would you use ThinkSuite?
If not, it's alright.
I'd really appreciate some feedback! Or if you'd like to try it out, join the mailing list, I plan to move to SF in a few months and we can meet up.