There are many crazy theories about the controversial ending of Mass Effect 3, but one of them has a really interesting point to it. If you remember, at the end of Mass Effect 3 Shepard is given three choices by the Harbinger: Control, Synthesis or Destroy the Reapers.
Well, many fans of the series think that this is just another manipulative move to indoctrinate Shepard and make him not destroy the Reapers after all, and here is why. The Destroy choice has a red color, which is nothing special at first, but when you think about it, you may remember that morality choices in ME3 are Paragon and Renegade, which correspond to good and evil, with the corresponding colors of blue and red.
So, if Shepard chooses to destroy the Reapers, then he will take the red choice, which makes him a bad character, and if he chooses to salvage them, then he will make a good choice, thus the theory of being manipulated by the Harbinger makes a lot of sense.