When the price per unit is at a level we'll call P1, it's like the demand team has scored more goals than the supply team. In other words, the quantity demanded (QD1) outstrips the quantity supplied (QS1). This is the equivalent of a fan frenzy - too many fans wanting limited game tickets! When this happens, there is 'excess demand', or a 'shortage'.

Imagine it as a hotdog stand at a soccer match - if there are more hungry fans (demand) than hotdogs (supply) at a certain price, the hotdog vendor can increase the price.

So, P1 is like a soccer ball that can't stay still - it's driven up by the intense game and isn't the final score.

On the other hand, when the price per unit is at a level we'll call P2, the supply team has scored more goals. Here, the quantity supplied (QS2) outpaces the quantity demanded (QD2). Picture a stadium that has more empty seats than spectators. This situation is called 'excess supply', or a 'surplus'.

Back to the soccer match example, if there are fewer fans willing to buy overpriced jerseys than the number of jerseys available, the price of jerseys will tend to fall.

Like a runaway soccer ball, P2 also isn't the final score. Because it causes a movement in price, it can't be the prevailing price in the market.