Answer: beacause if you dont know witch set it goes to then you will be confuesed of witch set it goes to.

Step-by-step explanation:

ex;

your mom tells you to put your siblings mess back onto its place then there are 3 places 1. the one for cars and areroplanes 2. the one for rockets and ships 3. the one for your siblings books.

if you dont know witch is witch (beacause there are no labels)

you puted it wrong

1. the areroplanes and cars is in #3

2. the rockets and ships are in #1

3. the books are in #2