Someone who is a user and abuser or User/abuser is a person who will use another person, usually in asking favors or special treatment, then purposely or even inadvertently abusing the relationship and thinking they are in the right. Often attributed to drug addicts and alcoholics yet can be a character trait of nearly anyone.

A person who befriends you and begins to ask you for things, like a ride, a cigarette, a couple of dollars etc.
Then one time they ask you for a favor and you cannot follow through because you don't have the time or resources and they belittle you, or get angry at you.
Other kinds of user-abusers will stretch their "Friendship" with you by asking more and more of you until you realize that they are truly abusing the relationship

When you eat dirt for the first time and leave your family to build a shack in the woods