If someone is like that then they were never your friend to begin with and honestly now that you see what they are all about you are better off without them.
There are a ton of people who care about you - you don't need someone like that around anyways. I gotta agree fake people rank in my top five things I cannot stand.
You know what sometimes makes that difficult, though you see them and know them for what they are others you are friends with don't always see it and will continue to hang out with them so it can be hard to stay away from them without alienating other friends.