You have a sense. So you make some calls. Read some articles. Talk through it with friends. Design some features. Build it out.
And then stop.
Someone else dissed it.
Doesn't get it.
Wouldn't use it.
And you listen. Why?
You were compelled to invest in your desire to solve a problem, or improve something, or make something happen. You did the research, talked to others who share the problem, and designed something to scratch the itch.
And then some guy--perhaps credible, perhaps not--says he doesn't get it and it blows you out of the water.
You're laying there, dazed, dripping wet on the mud at the edge of the river--hell, let's call it the river of startup goodness--and sit steaming in your own misery because...because...what was it? Someone didn't dig what you're doing?
It's easy to criticize. Just ask me for some criticism--I'll happily give you some; hell I'll criticize you for asking in the first place. Easy.
It's hard to solve. It's hard to discover. It's hard to build. It's hard to match what you build with what you're trying to solve.
Startups are hard.
And critics aren't building your startup. You are.
Every time you listen to that crap and consider changing direction, or revisiting old arguments you've already won, you're doing a disservice to yourself and those you aim to serve.
Make it about them. Meet them where they are, not where you want them to be, and definitely don't listen to the drive-by critics. If you feel disconnected from the mission, go back to that original pain, call around to your prospects and talk with them and see if they really do have that pain.
But then get back to it. You're got work to do, and questioning yourself at every bump isn't getting any of it done.
Dig in, go serve.