What have you had the hardest time teaching your child, behavior-wise?

So you have a screaming, stomper too huh? Mine is 10 years old and we have been having issues with this on a daily basis. In my case I think the problem is that she has not developed her organizational skills and tends to get frustrated when it takes her too long to do something. There have been several occasions where she has had to walk nicely up and down the stairs 50 times just to prove to me it can be done without stomping. If you slam the door you can open and shut it 50-100 times so I can be sure you know how to do it properly. Many times this child just needs someone to scoop her up in their arms and tell her not to sweat the small stuff. I am amazed at the pressure and homework these children are facing in fifth grade. As for the interrupting, I do not attend to the needs of someone who interrupts. My children know if you interrupt me it had better be because I need to call the fire department. Otherwise, you might have to wait in your room until it is your turn to talk. The trick here is to never forget to give them a turn to talk. If you do that they will never quit interrupting you because they will be afraid you are just putting them off. What kinds of methods do you use?