Dumb, but successful businesses
CNet has a post that refers to a Weirdtechnewshub article entitled Top 10 Dumbest Online Business Ideas That Made It Big Time. It's worth a look to see what kind of things have been successful that might not sound like a good idea.
To be a successful business a lot of things have to come together, including a product or service someone actually wants, the business acumen to develop and market it, financing, etc. Its never obvious (at least not to most of us) which ideas will work, and which won't. And lots of good ideas never go anywhere for various reasons.