The correct way to ask your question would be: "What should I say to be polite when greeting others?" To answer your question: I think it is perfectly fine to say any of the following. These would all seem polite/mostly formal to me: 1. Hello. 2. Hello, how are you? 3. Good morning. (perhaps a little more formal) 4. Good evening. (perhaps a little more formal) etc. Now the following would be informal: 1. Hi 2. Hey 3. Hi, how are you/ya? 4. Hey, how are you/ya? 5. Hey, how are you doing? etc. ********************************************************* Added comments: *"Hi," in my experience, is too short/curt to be considered formal. (but this is only an opinion) *Now, I know for a fact that "Good morning" is perfectly acceptable to use when saying hello during the morning hours. (I use this phrase every day when greeting my students during morning classes right up until noon.) It is not accurate to limit "good morning" to only those who have just woken up . Source: myself, American English

Oh, I think we are a lot less formal than many places/languages. In everyday language we use very little (if any) formality! If you are just passing someone on the street or see someone you hardly know, it is perfectly acceptable to say "hello" or "hi." The word "hey" should really be saved for those who know well, although it is becoming a very common word and used more freely, however I wouldn't use "hey" in a formal situation (like a business meeting) because it would show distrespect to those you are conversing with along with making it seem as though you are not there to work, but to have fun. Good morning and good evening may be used too, but they are probably less common. "Good morning" is usually a greeting used for waking up and "good night" is like a good-bye for someone going to bed. In parting, someone might say "Have a nice night." or "Have a good day."

why not use the best way to chat for the beginning?i think "hello" is the best chose for you to make a comunication ! even though "hello" is so easy to say,but it can also be polite.