To me, there is a major difference between quick and fast. That’s due to the fact, that quickly refers to time whereas fast will refer to speed.
With things done quickly, I associate the idea to have things happen in a short lap of time. Often the duration is an estimate and hope that things will not take a lot of time. The main consideration is how much time they take and less so, what their result is. Quite often things done quickly end up to have had too little thought with a need to invest more time to repair the problems which appeared.
When being fast, we still can be too fast and thus miss out on achieving the result. But achieving the result remains our main focus. So, even when being fast, the time used to achieve the result is not necessarily restricted and care for the result remains present.
In a similar approach, Michael Schrage distinguished between creating innovations for the pain customers experience in the here and now and creating innovations affecting who the customers want to become. The first being a tactical investment and the second being a strategic investment. Investing in the customers future, thus helping them to become who they want to become is creating value for them. This value serves both.
Enabling ourselves to be fast is a way to invest in our future. We allow ourselves to move towards who we seek to become and avoid losing time on doubt, resistance or any feature of human nature that slows us down to make sure everything is perfect.