Difference between actors/actresses and characters

I was amazed when earlier today I watched Cast Q&A on NBC.com for The Office. I saw how different most of the actors/actresses where from their characters. Angela is definitely the most different from her character, which she is also named Angela in The Office. Her character is very quiet, christian, old time and to see her she is just like the total opposite. Now in the Cast Q&A they couldn't decide who was the most like their character so they chose 2 people that they thought were pretty equally like their character and that was B.J. who plays as Ryan and Mindy who plays as Kelly. Now I don't see much of these characters so I can't really have my own opinion about that. Watch The Office :D <3