14. Thinking That Heimdall Can See Everything - (Thor)
Although it was relatively fair to assume that Heimdall - he who can see allover the universe - could see everything in and around Asgard, the fact is that he couldn't because Loki could get in and out (and allow others in and out) of the realm without Heimdall seeing him. The act of sheer dumbness is more due to the fact that the route Loki was using (as revealed in Thor: The Dark World) was only a short journey from where Heimdall stands while he's on duty. So why the hell couldn't he see it? And why didn't he know that he couldn't see it, given that it's his job to see everywhere and given that the area he couldn't see was so close? Surely there would have been a blank, hazy area as his eyes passed the hidden area? Simply baffling.