If you start by saying hello when you talk to a person first, you can strengthen your relationship with him and proceed with the conversation in a better state.
If you live by greeting people, you'll have more connections, I'm sure. Greeting people can be another charm of living life. Actually, the other person is waiting to say hello. If you don't say hello, the other person might think, "What is this?"
The same goes for:
Just say hello! 😫