I think that watching so many movies and series is not harmless for teenagers because:
While watching films and movies, you can learn so much – think about science, math, culture of a country, and so on. Also, watching so many films is always better than looking at the phone and just scrolling through Instagram or YouTube. But there is a problem as well when you are watching series. For example, ”How I Met Your Mother” is literally 10 seasons, and to finish it, you have to spend so many hours on it. It makes you dependent on it and you lose a lot of time for your other activities and responsibilities. If it is not too much, it is okay for you to watch movies and series, but if you lose control, that’s where the problems start arising around you.
In short, watching films and series is okay; it has many advantages. However, if you watch too much, the advantages turn out to be disadvantages. So, you need to balance the time you spend watching movies and series.