Television is an excellent medium either for training your wits or for killing time. However, American television does neither of these things properly.
There are several kinds of television in the world. Let's start with British television. I know about this mainly from Monty Python, Doctor Who, The Office, and Are You Being Served?. British television has obvious elements that make it enjoyable as an art. If you don't follow it closely, for one thing, it go on without you and you won't be able to keep track of anything. So, you can't keep half an eye on British television. It requests your attention by presenting a comedy show as if it were just a bunch of people walking around and not noticing that they are saying silly things. British drama, although I haven't watched much of it past some 1950s Out of the Unknown episodes, is acted plainly, as if it were a stage play, and the camera is not thrown into things to make it more gripping. So, British television is TV as a subtle, appreciable art form.
Japanese television is the exact opposite. Of course, there is the NHK which airs BBC-style television, for those who want it, but there are so many other shows too. When you watch a typical Japanese TV show, you will alternate between laughing, saying "Wow!" in utter amazement, and being knocked out of your chair by how bizarre and new something is. Freewheeling creativity is key for writing a good Japanese TV show. For example, there is a show where every week (or every day?!) the producers come up with several inventive ways to recycle old things, and the stand-in group rates them on a scale of 1 to 10 and makes witty comments. Having a small group of people giving their own reaction is another enjoyable element of Japanese TV-- even in anime, a spectacular scene will often be followed by someone saying "woah!", so the viewer hears a sort of echo of 50,000 other viewers saying the same thing, making the show more comfortable to watch. Even intellectual viewers have to admit that Japanese TV is extremely inventive and enjoyable, although it is often useless.
Now, we come to American television. American TV does not revolve around a viewer paying close attention to appreciate humor or drama, nor does it demand the show's producers and cast to come up with exciting new ideas all the time. Rather, it has seized on the easiest possible emotion to keep people watching-- intensity-- and written thirty years of uninteresting shows around this concept. Even the evening news is written around a sense of excitement that is entrancing yet somehow supremely boring. American TV is cheap to write and cheap to watch. Unlike British TV, the viewer is assumed to be a picky customer who will switch to another channel if the show isn't capturing his attention, so there is no subtlety-- laugh tracks abound. Unlike Japanese TV, the industry is wary of exciting new ideas, since if they flop it will mean less immediate ad revenue, so innovative proposals often get denied. Therefore, American TV is both bland and artless.