Imagine your favorite movie without special effects...you'd see a lot of green screens, 3d models, plain backgrounds and etc. Your favorite movie would most likely not be profitable. I found a YouTube clip of movies with and without effects.
Though I already knew adding an effect to a clip makes it look much better it still baffles me how much detail goes in to special effects as well as, how much time goes into it.




So much detail also goes in to how clips are shot as well. Technical issues like a wire showing can cause massive amounts of problems in post production. Close attention must be paid to the placement of actors. If an actors arm reaches outside of the green background that can lead to hours of rotoscoping.
It's small details like that, that make me appreciate movies a lot more. (Even if it has a crappy story.)