(This concerns realism as in following the laws of physics, not in any other sense.)
When watching movies I generally get frustrated with animation/CGI-people being totally ignorant about the laws of nature, in particular Newton's second and third law.
A prime example of this horror is from "The Day After Tomorrow", in the scene where the transport ship arrives in front of the library. This 1000-ton ship is moving at 2-3 mph, but stops when hitting a bus(!!!). Similar crazy stuff is abundant in most, if not all, films. Please be the exception, Iron Sky!
This being said, my opinion is not that everything should be hyper-realistic, suspension of disbelief is a legitimate trope, but as in the previous example this violation of physical laws does not contribute anything to the film, and it makes your eyes bleed.