I recommend parents say something like, “If you say that we don’t love or understand you, I’m just going to ignore it
If your child is ruling your household with his or her dramas or emotions, you have to stop the show. You have to get that child alone and say, “Listen, just because something is happening to you doesn’t make it a tragedy for everybody else. If I see you being over-dramatic, I’m going to send you to your room for 5 minutes to pull it together.” Sometimes kids will then react with, “You don’t understand me, nobody loves me.” I don’t have a lot of patience for that, personally. Your behavior right now is about getting people to feel sorry for you. You just want all this attention and it’s not healthy for you.”
I want to make that very clear: that kind of attention is not healthy for the child receiving it. It’s a pain in the neck for everybody else, but it’s also not healthy for that child. As a parent, you have to teach them how to manage their inner experience without making other people feel bad. Part of what they get out of that drama and attention-seeking is they make their parents and other kids feel like they have to take care of them. And I think you can deal with that directly by saying, “Don’t try to make me feel like I have to take care of every little thing that doesn’t go your way.”
Because we’re not talking about you being understood or loved, we’re talking about the fact that you broke up with your girlfriend and now you want to take it out on everybody else
There’s a saying I like: “There are two kinds of days for teenagers. Good days and days when things don’t go their way.” As a parent, your best tool is to manage behavior with a structured response. If your child is being rude or obnoxious to you because they’re upset about something that didn’t go their way, you can say, “Don’t talk to me that way, I don’t like it,” and leave. Another approach is to give them a different way to express themselves. Suggest, “Why don’t you write about it? I’m going to get you a journal. I want you to write all about your problems with your boyfriend there, and then once a night you can share it with me for five minutes.” So you put all these tools together and manage that child’s emotions until they can learn to manage them on their own. Again, you set an external structure with the hope that they’ll internalize it.
I think a special note has to be made for only children. I understand that this is a unique situation because these kids are the center of the family for a good part of their life. So as an infant, that child 
is always held, always gets special attention, always has two smiling faces looking at him or her. Only children don’t have to share their toys at Christmas, or feel jealous of any presents or attention their siblings receive. But remember this: it’s important for parents to shape that level of attention to develop things like empathy and consideration for others.
Don’t forget, empathy is an instinctual energy, but it still has to be developed. You may experience it as an emotion, but it’s also a drive that gets us outside of ourselves and thinking about others. If you’re an only child in a family, you don’t have to compete for computer time or video game time. You don’t ever have to say, “Well, it’s Ben’s turn, I guess I’ll let him go,” because you don’t have the opportunity to learn those kinds of lessons at home with siblings.
