An apt analogy that I always use is to think of a larger diameter, smaller pitch is just like running in first gear. LOTS of thrust at slow speeds, but no top end power. Make the diameter smaller, and increase the pitch, and it's like running the plane in second gear. Still a lot of low speed thrust, but the greatest thrust comes at a moderately slow speed. As the plane gets above this speed, the thrust drops off, and eventually reaches zero, but this point will be higher up in the speed range than the "first gear" prop. Continue this analogy and you have third, fourth, and overdrive. Since you dont get to change pros "gears" in flight, you have to choose what you want to do. Either go fast, but take more time getting there, or go slow, but accelerate to that slow speed rapidly; or some mixture of the two in between.