I had this discussion with a co-worker. While I think you shouldn't have hatred/distaste for your product or solution, I think it's more important that you have passion for helping your customers/clients in a good-for-everyone way. For this reason I'd ideally entrepreneur in the charity sector, because I have a passion for helping charity organizations.
There might be varying shades of grey to this argument. I'm a web application developer, and my co-worker would only pursue building ASP.NET websites related to his passion, music. Less extreme versions would be either building for any platform in any programming language, something music related. Or building ASP.NET web sites/services but not for music. Also varying definitions of "passion".