'Perfect' System

MARIO KART

Mario Kart has a good system which adjusted the system variables according to what position player is at. If a player is ahead of others, that player won't get as good item as compared to being in the last position. Everything in the game exist for a purpose and all affect each other directly and indirectly. For example, players position affects the probability of what is within the box they gotten and the item being used might affect the player  themselves or opponent but the item position and speed is affected by environment [mud, worm, water].  if the shell hit the corners [perhaps a wall] it might bounce back at player or at opponent.  The system does not limit much of what a player could do which gave players a certain degree of freedom of choices.

Negative feedback loop, always make the player feel they can catch up when behind but yet not too much to make it unfair for players ahead either.  Some information within the game is hidden and some open. You know what is the possibility of around the edge, but you don't know what the opponent might do.