I've only had one boy like that and he went through phases of tantrums at dropoff and pickup but he was awesome for me all day long. So I named him my Jeckyll & Hyde boy. I was constantly trying to get him under control, but part of the problem was that his Mom liked to chat for a while and the longer she talked the more he wanted her undivided attention and freaked out!

I learned a trick about pickups though, getting the child ready to go and excited to see their parent and in the mindset of going home to see their parents so they were calm about leaving daycare and ending their day.