I talk WAY too much when watching sporting events. I make calls for the officials, analyze play calls by the coach, suggest things that could/should be done, etc. I even stop and rewind the television and replay something in slow motion as I point out things that I think were interesting or shocking or strange about a given play during a game. I think it comes from my background of having been a radio sports announcer (football, basketball, and baseball) for a number of years.
For most other programs, I try to stay quiet, but I can't resist stopping a scene and replaying it (sometimes in slow motion) to point out to Mrs Media or to whomever is visiting and watching the show/movie with me some "behind the scenes analysis" of what is going on: composition of a particular shot (framing the picture by shooting through someone's bent arm or through intersecting tree branches, for example, or the way people in the shot are lined up in order to get every character in the shot or to emphasize the importance of a character, or leaving space behind a character in a dramatic moment to lead the viewer to expect something to happen behind the character), or perhaps to show how a scene is shot to make the actor blend smoothly with the action of a stunt person in a scene, etc. I think this comes from my Master's Degree in Communication Studies with an emphasis in Radio/TV/Film, and my past experience in teaching radio and TV courses.
With politics, I'll make comments or scoffing noises. Sometimes I'll make caustic comments at the TV, but that's usually when I watch Fox News.
Bottom line: If I were someone else, *I* wouldn't want to watch TV with me. I'm WAY too annoying. (And yes, Mrs Media is a saint.)