Forced comedic situations that weren't a result of the plot, corny wack ass self aware dialog, overly long action sequences, which numbed you to the great VFX.
That Avengers? About the only scene I enjoyed in the entire snooze fest is when they lured the Hulk in. Because it was a clever piece of screenwriting. And the dialogue was clever without being too ham handed. There is not one other memorable scene in the entire movie.
I remember reading about the scene where we are introduced to the Black Widow and thinking
And then I saw it on screen
He fukked it with corny dialogue.