Yes, our first and second ds's are very different. DS1 was a difficult baby (maybe more to do with that I was down after having him) but has only had 1 major tantrum, and apart from the usual kid whinging is generally great. DS 2 very different from the start.
DS2 very placid as a baby but behaviour now is quite naughty. He rips books, pulls out dvd's, crayons on walls etc, but then is so charming and cute with it.
Our first parents evening at nursery involved a lecture on biting and pushing. Last week, we got 2 reports of him fighting and he is only 20 months. He bites sometimes and has almost worn out the carpet on our stairs from the amount of time he spends on the naughty step!
He tantrums, squeals and cries when he doesnt get what he wants, then lays on the floor in a mood!
Im hoping he will grow out of it once he can communicate what he wants better. I go for the we dont hit etc, or a stern no, that is naughty and hurts. Everyone tells us to do it back to them and all have a story of themselves or someone else who had it done back and they never did it again, but i dont want to do that. We dont smack our kids.
He is learning and and is getting better. he knows now to go and say sorry too. Good luck.