It's so easy to focus on the negative or the hard stuff when it comes to parenting, but I think it's so important to recognize and appreciate when you catch kids in the act of doing something really good - above and beyond what is expected.
Last night as Gavin was finishing up his homework at the counter, Sam came and dumped his wagon of lego's at the base of the stool he was sitting at and walked away. Refused to clean it up. If you have any inkling of the state of my house on any given day, it would not surprise you that at 9 pm at night, I was perfectly happy to let the blocks stay there and go on with getting the kids to sleep.
Right after Gav finished up his homework, he bent down and starting picking up the blocks. It wasn't his mess, and we generally don't ask him to pick up after Sam. I told him not to worry about it, that he didn't need to do that, and he kept doing it, so I went to help him. Of course, Sam saw the attention Gavin received for good behavior and came over to help finish picking up.
I snuck Gav a dollar bill as a thank you. But it was worth a million bucks to me to catch him in the act of doing something just to be helpful (he's never been rewarded with money for doing something like this before - so that wasn't the motivation!).