Why do Trump supporters continue to support him, even when they should know better?

Trump's version of events. He tells people face to face what he is going to do, and then does the opposite when they leave the room.He tells his diplomats to go out and tell the American people what he is going to do, and then proceeds to correct them on Twitter. He tells reporters what he is going to do and then calls them "Fake News" when they report it.