If it failed, I would almost certainly be fired. I have never experienced the tension that I did when the owner and general manager met me by that display when they saw it on the way in that morning. (I didn't tell them I had designed it for easy removal--it looked semi-permanent.)
The result? Sales that had been flat for years, never rising above $6500/day at the shop location by the display more than doubled. Total sales broke $200,000 for the 13 days the display was up, and had never broken $100,000 for the 15 days of the festival.
I've always understood marketing. Even when I was only first learning to read I would rewrite signs and billboards in my head when the family would drive somewhere—making them more persuasive, more concise, etc.
At the same job, without telling anyone I computerized (early 90's) sales and inventory tracking on my home computer, which they eventually bought from me when they began to rely on it more and more.
Also, when management wouldn't spring for something I thought we needed, I recruited outside investors, bought what was needed, and paid back the investors from profits. (First investor made 50% on their investment over one weekend—which made it easy to get others.)