I expected Beatrice to choose Abnegation because that was her original faction. Instead Beatrice chose

Dauntless. She didn't know what she was going to choose until her blood fell.

I expected Beatrice's mom to be a Abnegation-born citizen. It turned out that I was wrong and her mom was a Dauntless-born citizen.

I expected Caleb to turn into a mean guy who was a part of the Erudite plan. Instead when he found out what the Erudite leaders were doing he dropped out of initiation.

Contrasts and Contradictions