Ahhh to be kid once again... even only in the photographers' eye. They are adorable, cure, little rascals. And yeah they can be mean sometimes but only when they are tired already.
They are interesting, hard to capture subjects. They are almost always on the move, credit that to their adrenaline pumping every minute. Shoot them at their eye level, shoot them when they are dirty. Be on the shutter priority setting and you will always be ready to capture those "Kodak" moments.