There are a lot of people who like to watch documentaries. I think there are many reasons why people watch documentaries. One reason could be that people watch documentaries to be educated and to get to know new things. Maybe the people just want to know new things about a topic because they need it for school or for their job.
Another reason why people watch documentaries is that they can socially interact with others. Because maybe their friends or their colleagues also watch this documentaries and then they can talk about that.
Some people may also watch this kind of TV program to escape from their daily troubles and to be distracted.
Other people just watch it to be entertained.
My parents for example often watch “Universum”, which are documentaries about history and many different topics. They watch it to learn new things and to be entertained.