good morning

If a kid rides to school in a car and gets out at the sidewalk that leads to the front door of the school, chances are that a teacher, principal, or both will open the car door. The first thing those education types say is “Good morning!” 
what to say
“Good morning” is the usual kid response, but many times he doesn’t say a word and heads for the door without even a smile. Saying anything to anyone for less than an hour since eyes closed time is torture to most of humanity. Humans were not wired to speak much before nine o’clock….except for those irritating people who like to talk in the morning. For them, the salutation "Good morning" means “let’s talk!”
consider the alternative
High on everyone’s list of things to consider should be a human social interaction experiment. That investigation would require those who speak before 9 a.m. to carry around a sign that says something meaningful. Meaningful is subjective, but the sign carrier should consider the audience. What about: Hey, you! Smile OR Hi! I’m just glad to be awake!
back to the school carpool line
Kids are powerless to change the social laws that govern their lives. They use silence to communicate their opinion about the rules that govern them. When faced with a teacher opening their car door and saying “good morning,” each kid chooses to respond or to keep walking. 
The question is...how will the greeter feel about that kid?