The oldest gets the priveledges and the freedom, the new clothes, the new toys, always gets to sit in the front while in the car etc etc.
The youngest gets the attention. The youngest is usually spoiled for being the cutest and looked after the best because they're the most fragile.
The middle child will often get lost in the crowd, left behind, forgotten about. Gets no freedom or attention, has 'hand-me-down' clothes and toys from the oldest, is never heard, has to follow the rules of the youngest and gets the same punishments as the oldest.
The oldest and the youngest both have roles', one being the leader and one being the baby. Middle child syndrome is where the child lacks self esteem and a feeling of purpose...
I've had the pleasure of playing every role; being the oldest is by far the best!