Unnescissary CGI
Ok, some things would obviously need to be CGI such as him daydreaming about blowing up the office, but I hope others would agree that some of the bits were totally unnescissary. For instance the hummingbird, especially the slow motion shot. They could have used high speed photography there and it would look spectacular, but instead it just looks like really fake mediocre CGI. Ditto for the planes passing overhead, him looking out his window, the landing gear (and what was even the point of that scene?).
And if you are going to say that it was appropriate because it was meant to convey the fact that we are not in reality, then at least give a good explination of how that is supposed to fit into the overall look of the movie, because that is the one reason I could think of for it, but due to the plotting, and the conventional look of everything else I am not sure that is the case.
"No man is just a number"