Cats may step on their hair for the following reasons:

Instinctive behavior: This is something they have had since childhood Instinct may make them feel reassured and comfortable.

Marking territory: Leaving their scent in this way shows that this is their territory.

Reminiscent of their childhood: Stepping on milk may remind them of the good times with their mother cats.

Relaxation: It is a way to relax and reduce stress.

Close to the owner: Show their trust and love for the owner.

Soft hair: The soft texture of the hair may be similar to what they were exposed to as a child.