Don't you appreciate having someone who will just listen to you from time to time? I mean, just listen for awhile, without interrupting to tell you how you're wrong or to offer suggestions. Yes, a good friend will not allow you to wallow forever, but might sometimes just let you air your feelings before helping you to see things more clearly.
I've realized that kids need that, too, sometimes. My son needs a safe place to "vent" his frustrations and get his thoughts out in the open. Kids need that as much as we do at times! Of course, we mustn't tolerate or allow inappropriate behavior (temper tantrums, destruction of property or people, vicious language, etc.), but neither do we need to correct every word the second it comes out of their mouths.
There is a time for correction. After they've said what's on their minds. Again, appropriately!
I think I surprise my 10-year-old son when I just listen and acknowledge that I'm hearing what he's saying, but don't interject my commentary for awhile. And I've learned (notice the word learned--it's definitely taken awhile!) that when I just listen and let him talk, I find out more of what he's thinking and feeling--what's behind the anger.
As I mentioned earlier, there does come a time when it's his turn to listen. I try to sympathize where appropriate, but also hold him accountable for any faulty thoughts/actions/words of his own that contributed to the situation.
Prayer is vital in correction as well. Only God changes hearts. We want more than behavior modification in our children, right? God works through us in that, but only He can change their hearts.
So, let 'em vent (appropriately) once in awhile! When there's time. It's okay, and even good. :)