I'm wondering why is it so hard for parents to understand their teenage child. I mean they once was that age before, and even they know that they had to grow up and live their own lives. So why is parents so hard on their teenagers?

They are only like this because they remember the crazy stuff they did growing up and are trying to protect you. What they forget is this stuff is part of life and they turned out just fine and thet by holding you back they just make you want to do it more

I also need help with this answer, but I think its because that the parents are scared that their child would follow the wrong steps, just as they did. They had the same parents telling them in their ear consistently that they need to do this and do that. So their parents just want their child to do right, without the child trying to understand. We all know that there is nothing like bringing life into this world, so that is why parents become so over protective over and over again. Years and years to come. All teenagers must know and understand this, there is no harm, no foul, but there is something called love. Even if a parent have lost your trust, they still worry and care for you now matter how hard you think they come off as.

Most parents want better for their children. They want to help them avoid the errors in judgement that they may have made... whether that was choosing things that could be potentially harmful or not getting involved in things they wish they had taken the chance on.

Each generation has to learn a certain amount on their own, parents hope that they can at least help their children avoid the major issues that can have life long repercussions.

I think it also is more difficult at times because so much of what is heard about teens, through the media, tends to be negative. Parents know that teens simply do not think the way most adults do; teens naturally tend to take more risks and are less aware that bad things really can happen to them and not just to other people. Parents worry their children will be swayed by peers or media images into making some poor decisions.

Then it all starts over again when those teens grow up and have their own children... :)

I think it is mostly because parents know what they did and what they went through as a child. They want to mostly protect their child and also to try to understand where they are coming from. Just because you were once a teenager doesn't necessarily mean that you now know everything about all teenagers. Things change in time. I know a lot of dangers have appeared lately that just weren't as present when I was a teenager. I guess in the end all you can do is talk to your child and hope that you raised you child to be responsible enough to deal with the problems that will arise. Sometimes fear gets the best of us.. In high school I had a few really good friends that died of drug overdoses and suicides so I am particularly over anxious about those topics.

When I was a teenager, I was an idiot.

Because we did stupid things and if we didn't we know someone who did and in our love and desire to protect you we often over do it.Its a dangerous time,kids drinking and driving ,speeding,doing drugs ,having unprotected sex. Those are all real issues and any parent who would just let you do whatever is a fool.
There should be compromise and rules that are reasonable.Remember that trust is a gift that is earned.

In my opinon, it's not that the parents don't "trust" them, it's that the parents know what goes on behind closed doors. They want what's best for their children-in a sense meaning they don't want their children to make the same mistakes they did. On one hand, that's fine, but on the other their children will not know how to really face the world when they get out there if the parents are too untrusting and overprotective. Mistakes are life lessons which are better made early so that you can use the lessons.

I have to agree with all the above.

I was a wild teen and I know the consequences of those actions, I don't want my kids to go through the same stuff I did. I learned the hard way, they don't have to.

We don't all get out of our teen experiences alive or intact, yes, some lessons you have to learn, others you can avoid if you listen.