There are things that can be influenced or changed by our actions. There are other things which cannot be.
The area formed by these things that we can control and change to shape our destiny is called our locus of control.
You want to start your own company and roll out a product that you think will make the crowd go crazy.
Now, this is an idea that falls under your locus of control. You can work hard, do all the necessary things to transform that idea into reality.
However, whether that product will actually turn out to be appealing to the market or not and be hugely successful, that's something which falls outside your area of influence.
You can only do things right and hope for the best. If things don't turn out to be the way you expect them to, you can learn from the situation and try to improve your strategy for the future.
Weeping or worrying too much about something that's outside your locus of control is useless. It's only a grand waste of your limited time on this planet.
Don't worry too much about things that you can't control and instead put all of your energy into things that you can actually control.
That's how you live a sane life and progress.