It's a well known fact that TV steals time. You sit in front of it just for a minute to catch up on latest news, and a moment later it turns out that four hours passed. You have two choices, to get rid of the TV set altogether, or to make the most of your time in front of it. Since for most people not having a TV is unthinkable, you might as well spend the time watching your favorite shows, but instead of it going to a waste, learn as much as you can.
No matter if you like medical dramas, reality competition or celebrity scandal shows, there is always something you ca learn, just as long as you're not watching absentmindedly, but pay attention to what you see on the screen. To start off you need to remember that even if it's news, a reality show or a documentary, it's still sort of entertainment, so the information shouldn't be taken at a face value but be verified either by watching other shows on the subject, by reading books or checking online. The more sources you reach for, the clearer your picture will be.
When you watch a favorite show, be an active viewer. It doesn't mean you're supposed to write the producers after each episode or sit with your hand on the mini mouse just waiting to click on a vote determining who wins and who goes home. It means that you're supposed to take in the whole show and file away useful information. If you're watching a culinary competition, pay attention to what ingredients the participants mixed to achieve a unique combination; if you're watching a crime drama, try to figure out who the criminal is; if you're watching news, see if there are any connections between the weather and the sports results or between a new state law and price increases.
You should not only actively watch your favorite shows, you should also use them as a practice basis. Training your mind will have benefits in your everyday life, so you might as well use TV in your exercise working on your logical connections, memory, interpersonal skills, developing your database of music, quotes and even one-liners. Real people as well as scripted characters you watch say and do a lot of things on the shows they're on, so you can use that to broaden your knowledge, learn a new skill, and instead of just stare at the screen you can try cooking with your favorite TV chef, use a show's plot to start up a water cooler conversation or convince your boss to a new idea using some valid arguments you remember a character use.
It's good to have hobbies and interests that keep you outdoors and spending time with others, but at the same time it's okay to get home from work and sit down on the couch to watch some TV. The thing is you have to be smart about it and not become a slave watching all possible shows on each night and recording the rest to catch up on the weekends, and you also need to think when you watch your shows, whether they're about animals or sports, so you retain some knowledge and have the use of the show somehow in the future.