For a suggestion on why do some people hate you... there's a statement that I would like to share: "You can't please everyone." And while it may be admirable to try to make everyone happy, you obviously can't do it or else you would wear yourself out. For those that constantly hate you, there's three steps for this:
1. Ignore. This usually deprives them of a reaction and they move on.
2. Report. Depending on where you are, having an authority figure help you out will get them off of your back.
3. Self-Defense (within reasonable force). If things have escalated to this, know how to defend yourself if you should be attacked. This step may come before 2, but most likely will not be needed.