In general, normal behavior is behavior that does not interfere with a person's ability to cope with his environment or to get along with others.
Become Aware of the Attitudes and Behaviors of Adolescents Your Child's Age
However, you must consider your teenager's peer group and take into account the behaviors and actions of his age mates in order to determine if your teenager's behavior is typical or should be of concern.
Here in lies a particular problem as who are the kids peers and how exactly does he or she pick them. I as a parent always hope for kids (Our) to pick peers that are better than them and help them raise the level of their game. By choosing peers\boyfriends with low standards you are already setting the bar pretty low.
Some peer groups are themselves deviant, and may be associated with serious impairments or difficulties.
Not sure how to address this as we have little say in that and when we help choose them we get resentment and ill guided behavior.
Consider Individual Differences
Children have different personalities. One child may be sensitive, another talkative, a third shy, and so forth. In determining whether behavior is normal. Other parents are going through the same thing. Parents with multiple children sometimes have some that behave according and others that do not. They are all different.