Have you ever noticed that when you greet someone they usually say the same thing back to you? If you haven't you should test it out ASAP.
Let me give you an example. If you walk up to someone and say "Good Morning", they will most likely respond with the same "Good Morning". This seems logical but it gets better.
It doesn't matter what you say as long as it is a common greeting. You could say hey, hi, hello, howdy, what's up, what's going on, or even buenos dias and the person will respond with the same greeting a vast majority of the time.
Think of how you can use this to your advantage.
If you want someone to greet you positively, all you have to do is first approach others with a positive greeting, attitude, and smile. I think it has something to do with that treat others the way you want to be treated and love your neighbor as yourself kinda thing.
Try it out and see if it works. It isn't fail-proof but it does work more often than not. Worst case scenario is you positively greeted some people and were a bright spot in their day.
If you do it everyday, you can slowly begin to change the attitude of a person, classroom, school, office, business, church, organization, neighborhood, world...
Again, don't take my word for it. Try it out for yourself and see if it works. I think you'll like the results. Guaranteed or your money back.