Founding a startup has become a mythic type of venture, a unicorn of the business world. Your plans, your ideas, your company and your product. Founders of successful startups make enough money to make any ambitious entrepreneur drool.

It’s more dangerous than the rhetoric will make one think. Startups are an emotional roller coaster, with days where the founder finds themselves feeling on top of the world and others where they dread the days to come.

Hiring can be a challenge too. It can be difficult to find prospective employees who are willing to abandon their comfortable office jobs at established companies and work at a startup.

This is because working startups require a vast amount more effort than established companies with established infrastructure. Startups don’t have established infrastructure. Anything that gets done will be done by the hands of the employees.

Startups are intensely market dependent. In a poor market with few customers, the best startup in the world will still fail. Conversely, a mediocre startup with an acceptable product will do very well in a good market.

Unless the founder of the startup is talented at reading their market, they can fail despite any amount of hard work or innovative thinking. It’s difficult-although not impossible-to create a market from nothing.

Matching your product to the market is essential in overcoming this challenge. Rachleff’s Corollary of Startup Success says that it’s easy to tell when your product and your market aren’t fitting. The customers don’t seem to quite understand the product and don’t communicate with one another.

When your product fits the market, it’s explosive. Customers are buying products are fast as they can be produced, you’re hiring staff as fast as you can, and customer funds are piling up in the company account.

Being flexible enough to change your product or service to fit your market is one key to obtaining the product-market fit you want. Startups can fail because the product never quite fit the market it was intended for and the designers did nothing to change it to fit.