The [Therac-25](https://en.wikipedia.org/wiki/Therac-25) incident is a well known issue where the users of the product became far more proficient with it than the testers were. This caused a race condition which uncovered a defect. Historically, I have found that timing matters when testing. How quickly, or slowly, you click something or submit data can uncover different issues.

Does anyone have any experience setting up a framework that will test how the system handles different levels of waits between different actions?

To give an example of a scenario:

An application I was load testing passed all tests under a heavy load. While reviewing the code, I noticed a flaw in the design of the system where if there was a very small, consistent load than it would use an immense amount of resources and run constantly against a very small amount of work. I set up a load test that simulated the conditions and verified my findings and sent it back to Development. While this was a performance issue and a performance test, this type of scenario could potentially uncover a functional issue.