Oh, wow, you must be a total expert on mental fatigue and bonking, having clearly never experienced it yourself. I mean, it's not like it's a real thing that happens to even the most trained and prepared riders. Nope, it's just a matter of "pushing through the pain and discomfort" and suddenly, magically, your legs will start working again. And please, do go on about how positive self-talk and visualization are just "fluff" - I'm sure your negativity and skepticism will totally help you power through that next climb.