These are what I've observed about kids:
#1 They are easily distracted by anything, especially computers!
#2 They get amazed about something easily. Eg I stacked up some wheels into two piles which they said that was a castle and was very happy.
#3 They dislike/hate losing a game! Some cried, some just said "I don't want to play already".
#4 They can run fast. Especially along the corridor.
#5 They love to talk. Eg They love talking about their school/tuition or family stuffs.
#6 They (especially boys!) dislike being copied by another. Eg If another kid is looking at his paper/worksheet, he will immediately use his arm to cover it and say "Don't copy me".
#7 They get excited and contented easily. (Maybe that's why kids are always the innocent ones!) Eg They have to be well-behaved in order to get stickers. If not, stickers given will be taken away and they usually will say in a sweet voice "Can I have a second chance?". Seems like they want the stickers very badly.