Following up on a smart idea from @andrewchen, here is a good set of answers to "why startups fail," one of the most common startup questions on Quora:
If you are starting a company and you don't think you're exceptionally suited to solve the problem you're solving, stop. The likely conclusion is death.
Also, if you look around at your co-founders and you're like "meh," STOP NOW.
a) users don't exist. Your thesis about the world was wrong. If you're starting to get clear about this, think carefully.
b) users aren't impressed enough.
c) users are too expensive to capture.
Often, problems stare you in the face for months. You do nothing about them bc
a) "it's fine"
b) another crisis is taking up your attention.