When I first came to Japan, like so many others, I started working in an English conversation school, or "eikaiwa" as they are known. The first time I walked into a classroom I greeted the students, about 4, by saying "Hi, how are you?", a pretty normal sort of greeting. The confident responses I got left me completely baffled. "I'm sleepy", "I'm hungry", "I'm thirsty", "I'm sleepy, too". How does one continue a conversation from this point?
I was to, and continue to, encounter this oddity in the use of the English language in a variety of situations and circumstances. These people were not young children, they were not 3 years old. They were teenagers, adults, intelligent people! Who was responsible?
It didn't take very many questions to discover they had learnt it at school. It seems that "Greetings" have been used, in Japan, as a convenient means of teaching an irrelevant set of adjectives describing feelings or conditions. Point the finger where ever you like. If you are teaching in Primary Schools, ask yourself how many native speaking 6 year olds you know use expressions like "I'm sleepy." to greet strangers.

What is a greeting?
You can look it up in your dictionary if you like. Look it up on Wikipedia. Ask your friends. When you meet new people, or people you know (native English speakers), listen to what that say. What actual is a NORMAL greeting. Let's have some dialogue about it. My 'personal' view, is that a greeting, when used in conversation, is used as a prelude to that conversation. If you do not know the person, then you probably introduce yourself first, and then greet (or the other way around, if you like). If you do know the person, you usually greet and then enter into some kind of conversation. Whatever the case, a greeting sets people up for continuing dialogue. It is probably the most important conversation you have to teach to a student wanting to learn a new language.

I am an Australian, so in addition to teaching 'formal' or 'textbook' responses like "I'm fine, thank you", I teach students what I would usually use with another native speaker. "How's it going?", "Hi.", "Good." "I'm OK.", "Not bad, thanks.", "Yeah, all right, thanks." The list goes on. If you come from North America or Jamaica, then you no doubt use other forms of greeting. TEACH THEM! They are your culture!