I like to remember the respect rule of thumb that is mentioned above here. However, it won't always work to your benefit. Like if you treat someone with as little respect that they show you, by never holding something if they need a hand, never moving if they're in your way, never doing you a small favour, you might be labelled just as disrespectful/distasteful yourself. And if you confront this person, you might be told that you're just the same yourself.