In 2005 I worked in pizza delivery and I thought it would be great if we could set up a call center that people could order whatever food they wanted, from whatever restaurant and get it delivered to them.
I had the business plan drawn up, the name was going to be "Ding Dong Dish". I presented it to potential investors because I sure didn't have the money to pull it off, but I was told that the idea would never take off.
To be honest, they were probably right at that day and age but boy did it ever take off when the time and technology were right.