As a mtb racer and a coach I am always looking for ways to improve my riding and my coaching too and like you, the faster the better. The funny thing is, we ignore, gloss over and just don't want to talk about the thing that really holds us back from reaching our goals in all aspects of life. Our focus tends to be on the physical; "what are the mechanics of a j-hop?", "what should my body position be in a corner?", "will these lighter wheels will make me faster?", when it is our mind that is holding us back.
In the past we have stressed the value of positive self-talk ("I am a good descender and getting better at climbing with practice.") which is far and away is better than negative self talk but turns out not near as good as interrogative self-talk. Interrogative self-talk is asking, "Can I do this?"....
Positive self-talk makes you feel good and possibly confident while interrogative self-talk prompts you to come up with ways to accomplish the task.
Before or during your next ride instead of declaring your abilities with positive self-talk simply ask yourself, "can I do this?".