Actually, it's about manipulation.
All art, whether it be writing, acting, music, film, painting, drawing, etc, is created with the idea to manipulate the recipient in some way.
We want to make them feel something, evoke an emotional response that is directly the reaction of their psyche to our work. And as consumers of art, know we are being manipulated. We listen to a favorite song because it lifts our spirits. We have "Comfort" books and movies that we read or watch on a regular basis because they bring out positive feelings. We watch a scary movie at Halloween to get into the spirit.
That is all well and good and the nature of art. It's why we do what we do and why we listen to music, watch movies, and read books. Where it gets sticky is when the creator manipulates with a sledge hammer.
This can happen in any format, and is often the result of the creator not being confident in their work, or in the case of a long time series or TV show, feeling they need to "shake things up". TV even has a nice little term for it- jumping the shark. Came around when the show Happy Days decided to liven things up late in their run by having The Fonz jump a shark.
It didn't liven them up, but did make them a catch phrase (and not in a good way).
More recently TV shows are doing this by killing established characters. The actor wants off, or someone else wants them off, so they ratchet up the emotional level, then kill them. See my previous post on killing- if it's not essential to the story, and there was another more logical way to complete said story- don't do it. Don't let me as the reader see the strings being pulled.
I know I am being manipulated in my emotional reaction to what I read, watch, and listen to, but I want it to be subtle. When it's done with a light touch, the reader gets pulled in and easily finds themselves reacting to the work appropriately- aka they dance the way you want them to. But when things are too over the top, too much for shock, or you find yourself wondering how to get that character on the water skis to jump that shark, there's a problem. When people see the manipulation, the "man behind the curtain" it ruins the magic.