The event that unified the Avengers was the untimely demise of SHIELD Agent Phil Coulson. Having featured in previous Marvel films, and clearly idolising Captain America, audiences were somewhat attached to Clark Greggs character. When Lokis plan to divide the Avengers was nearly complete, Coulson took the biggest weapon he could find and shot Loki with it, however he was killed in this process. This was a heart-wrenching scene, and audiences were genuinely choked up by this heroic sacrifice. And then the Agents of SHIELD TV show happened. Coulson was revived with advanced technology under the orders of Nick Fury, and he is now the star of his very own TV show. This spin off struggled to find its feet at first, although it has improved with its second season, but the fact that Coulson did not really die completely negates his death and the unifying point of the movie. It has removed the emotion from a scene built on emotion.