I've been an entrepreneur for 25 years. My first business I started in an industry/business I was interested in. Bootstrapped it and had lots of fun 70+ hour weeks. I liked the industry and found it interesting, but in hindsight it didn't meet a lot of what I wanted out of my business/life.

In my subsequent businesses, I started with a new approach. My first question was what were the things I wanted personally and professionally to have and what businesses/industries did I think best supported those goals. Along with that I matched those industries with where I saw business opportunities. That was a WAY better approach! I think you can do both in terms of defining your personal/business goals and interests first and then match that up with where there are opportunities. My result was I made more money, worked on the parts of the business I was best at and enjoyed most and was able to balance it with my family life. I would say the best of both worlds.