1. Build something you are personally passionate about. You are your best focus group. The first statement is great. The second is potentially dangerous and

1. Build something you are personally passionate about. You are your best focus group. The first statement is great. The second is potentially dangerous and stupid if your reality distortion field is strongly polarized against what a real market wants. Do your homework and get real market research. Find a pain point or a genuine need. Believing that you're right and everyone else is wrong is a greased pole to hell in most cases. Caveat emptor.