It's rude to slam doors.
Timmy's mom works odd hours and is often sleeping when he leaves for school.
Timmy wants to make sure the front door is secured when he leaves for school.
Timmy gently closes the door before locking it.
Timmy slams the door shut on his way out of the house in the morning.
Timmy's mother is able to get a restful night's sleep and has enough energy to get through her work day.
Timmy's mom is awakened by the loud noise and arrives to work grouchy and unrested.