Answer:
Black we are and much admired. Many seek us if they are tired. We tire the horse, and comfort man, and turn White when we've fulfilled your plan.
Runs smoother than any rhyme, loves to fall but cannot climb.
What is neither inside the house nor outside the house but a necessity for any home?
A box without hinges, lock or key, yet golden treasure lies within.
A house full, a yard full, a chimney full, no one can get a spoonful.
What never gets any wetter no matter how hard it rains?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?