I'm a fairly critical person when it comes to books, movies and television. This probably has a lot of roots in my schooling -- as an English student in college it became ingrained in me to be very critical of everything that I read, and I've carried that on to this day. Of course, I can let go of that for certain types of movies, but let's say I'm watching a show or movie that was supposed to be critically acclaimed or that is taking itself seriously as a piece of art, I'm going to be much more critical of it.
Of the options listed, I'm probably most critical about writing, probably for the reasons I've already mentioned. I feel like you can have the best actors in the world, but a bad script or premise is going to doom the whole production. Take a look at the Star Wars prequels; there were some really talented actors in those movies, but there's no way they could have done anything with the crap they were handed.
What about you?