Teenagers can be frustrating and challenging people to deal with. Many times I have been in the situation where a student's behavior in class has been highly disruptive and left me feeling frustrated and then when I talk to students about their behavior, I get sucked into talking and talking and what I am saying falls on deaf ears.
When I try to think of the students perspective in all of this I guess being told off by a teacher is never pleasant - lecturing, drilling, droning on about the behavior just falls on deaf ears because it is easier for kids to zone out (and therefore avoid feeling bad about the behavior) rather than listening to a teacher deliver a long criticizing discourse. So, my suggestion is this, maximize the potential of your discussion with a student by following the 60 second rule - get your point across in a shorter period of time.
In teacher terms; Quality rather than quantity, be short, concise and honest about the behavior that you would like to address. Deliver the message in under 60 seconds and increase the likelihood of being listened to.
'When it comes to talking to a student about their behavior - less is more.'