Teenagers are not wild animals. They are not stupid or incapable of understanding things. They are not useless without a WiFi connection, and they are definitely not interested in anything adults have to say (or in having a clean bedroom). What teenagers are is undefinable. Go ahead and ask them: they will tell you they don't know, and they don't want anyone to slap a label on them.
Parenting is hard, yes. So is being a teenager. The P.E. locker room can be a terrifying place when you are 14 ...and so can the dinner table if your report card isn't what your parents expect. Teens have one job: to figure out who they are and learn how to function as that person in the world. When things are messy at home or at school, it gets even more complicated. Throw in some confusion about sexual orientation, peer pressure, the huge number of decisions teens are expected to make about their future, added to everyone's expectations of them, and it is easy to understand how teens and tweens can experience shame, fear, anger, confusion and frustration--all of which distract from what their parents care the most about: doing well in school and staying out of trouble.
Like most parents, I have indeed said, "I was a teenager once myself and I remember what it was like". Unfortunately, that was then and this is now. Things have changed a lot. Technology has made gratification and access to information instantaneous, school has more homework, parents have less time, things happen faster/sooner, families break apart and reconstitute themselves, and the traps into which a teenager can fall and lose their way are easier than ever to stumble into.
How helpful would be to have someone supportive in your corner, someone whose only goal is to help you succeed as an individual, without bias, pressure, or judgment. Someone who will listen to you (and your music and YouTube stuff). Someone who is not a teacher, parent or someone who will judge you in any way--just someone to help you figure stuff out. Providing this sort of support is a big part of why I chose this career.