product market fit vs passion market fit

Before product-market fit, find passion-market fit.
The only way you’re likely to find product-market fit is if you’re almost irrationally obsessed with the market and if you’ve been working on it for a long time. Where the journey itself is the reward. Then, you’re likely to have unique insights (in the details) and consistent execution, through thick and thin, to find fit.
Here is a fantastic blog post on this topic: http://venturehacks.com/articles/passion-market

Why startup?

If you are doing it only for money, you are doing it wrong.

Obviously, monetary economics have to exist, however, that should not be first motive for founders. Instead, company building should come first and monetary results will almost always follow the company building process.

The main reason why I started the company - passion for creating great products and burning desire to change the world. The following quote comes to our rescue:

"Customers love great products that solve a clear pain-point.
Great products are built by great teams. 
Great teams in turn attract great people."

So, get out and start building a great team that is focussed on executing a clear mission.

To sum up, I'll be happier if we make money but will be downright upset if we can't win and build a great company.