Just seen nbg's thread and read some other examples of teenagers being intimidating so perhaps some of you will be up for getting some gripes off your chest too.
This is mine: I live on a main road and the teenagers round here seem to have developed a new way of crossing the road. Firstly they completely ignore the crossing island about ten feet away - well, OK so would I have done when I was a teenager.
Then they cross the road, but do not wait for a clear road. They sort of walk half way across the first carriageway, stop, block the traffic - literally cars and lorries and buses all have to come to a complete stand still - while they wait for the other carriageway to be empty. Often someone in the other direction then has to slow down just to let them cross as they can see the stopped traffic on the other side.
If they really can't use the traffic island, couldn't they at least walk into the middle of the road and allow traffic to pass on either side of them? Why do they have to stop in the middle of the carriageway and why do drivers not hoot them out the way?
Why does it infuriate me so much? Well partly because I am a cantankerous old woman but principally at the moment because I want my nine year old ds to gain some independence soon and want him to be able to cross the road safely. He won't if he sees what his elders are doing.
I could add some more complaints too, but I don't want to appear too cantankerous all at once! 
Anyone else want to off load?