You can never let your data dictate design. If you do, you end up following what people currently do and never innovating.
Never use a warning when you mean undo.
Your first try will be wrong. Budget and design for it.
To the user, the interface is the product.
Find a faster way to fail, recover, and try again.
When you are solving a difficult problem re-ask the problem so that your solution helps you learn faster. Find a faster way to fail, recover, and try again. If the problem you are trying to solve involves creating a magnum opus, you are solving the wrong problem.