Hmmm... most social rules generally want people to behave in a predictable ways, for various reasons, so they avoid surprises. It seems almost like surprises are only allowed in special cases...

I almost accept your point now, but one objection. A good and a weak soccer teams play a match. Surprisingly, the weaker one wins. It was fair play. Nobody violated a rule. Still the fans of the losing one are angry - at their own team, because how could they let a much weaker team win. Is that a social rule violation that if you are generally better you are never allowed to lose? Or just an expectation violation? Is it more of a bias on the side of fans: their team must have violated to rule to try hard and not be lazy, because they cannot imagine any other explanation?

If you generally agree, I accept your point with a modification: anger is about perceived social rule violation: but people are not perfect judges of social rule violations, there are mistakes made both ways, and tententious, bias-driven mistakes.

Thus, as in my soccer example, sometimes all you see at first is a violated expectation. You see no rule violation. Then you need to figure out why exactly may other people think it is a rule violation. This is not always easy and we don't do it that often, and thus often we just see a violated expectation, and not see how others perceive it as a rule-violation.