Time for a quick multiple choice, one-question quiz.
What makes a good wrestling swerve? Is it A) complete and utter surprise, shock and satisfying pay off afterwards, B) a one-off move just so bookers can scream, "I told you so!", or C) putting Steve Austin in the Alliance because there's a serious lack of star power on the WCW/ECW side?
If you answered A, congratulations. You're not a B+ player like Daniel Bryan, and you've got it right. Any good swerve, even if it was only conceptualised days or hours before, needs to successfully trick the audience's expectations and then deliver some story follow-up that justifies the original decision. This can be difficult, because the temptation is there to pull off swerves without true depth or explanation afterwards.
The best swerves are those that marry unpredictability with good narrative. They should leave fans with a coy smile, and enjoying that moment of astonishment when brain matter collides with vision to establish that they have indeed been hoodwinked.
These are the best examples of swerves that weren't done for the sake of it. Instead, they all had a game plan and ended up being better for that pre-planning. Each one worked a treat...