How come my 17 year old does whatever he wants and doesn't respect his parents?

He's been taught : The most helpful thing i can say about this, may not be very welcome . . . But kids learn how to act and treat their parents, from the parents themselves. Consistency and a united front are important in dealing with kids, especially adolescents who are testing boundaries. A 17 year old is almost out of the house. You could consider family counseling -- including parental counseling -- very soon.