Why take "good morning" seriously? Here is my good morning teacher manifesto:

1. "Good morning" is a way of acknowledging there are other human beings out there. It is nice to say it. It is good to say it. Harmless even.
2. "Good morning" is the first thing you say in the morning and it should be said the nicest way possible.
3. "Good morning" is a warm welcome when said in a school environment. Naming it a "good morning", you simply make it one.
4. Not everybody feels good in the mornings, nor everybody comes from lovely cosy homes having had a wonderful breakfast. Your good morning can be the only good thing said to some of them so say it generously. Say countless good mornings in case they warm someone's day who may need it badly.
5. "Good morning, teacher!" is the first thing you hear in the morning at school. Students seem like they like speaking English only in the mornings. Don't let the chance slip away! Answer them "good morning!"