Some teens feel invisible or entitled, which usually doesn't leave much room for them to listen, learn or show patience and gratitude towards parents and adults. But to answer the question how to handle teens who think they are adults, is a very broad question. If the teen thinks they know everything and that attitude is getting them in to trouble by not listening to parents, teachers or adults and they are violating parental or school rules, laws and or getting unacceptable grades then there should be some consequences. Taking away teen privileges can be a good way to get there attention. Example if a teen is coming in late after curfew then they should not be allow to go out for awhile, or maybe there driving privileges should be suspended for awhile. If a teen isn't getting acceptable grades then maybe: cell phone, tv, computer or free time with friends needs to be taken away or cut down to a minimum until the teen shows improvement. I feel the consequences or punishment given to the teen should relate to the problem so their is a direct correlation and more of an understanding of what needs to be fixed.