I am of the generation that discovered the television show Beverly Hills 90210: No, Not the New One--Shut Up and Get Off My Lawn. This was back when TV shows were all basically produced by the big networks, and as a result they tended to be very bland and predictable, because they were geared toward not offending anybody.
In contrast, the first season of 90210 was delightfully shocking. For example, you had a character named Kelly, who was super-duper popular. Why was she popular? Because she lost her virginity at the age of 14, when she was a freshman, and the guy she lost it to was a senior. She wielded this fact like a cudgel--you're telling her what to do? Well, honey, are you so hot that you lost your virginity at age 14 to a senior? Guess not!
Trust me, at that time, nooooooobody was suggesting in a teen-oriented show that having sex could make you popular in high school, especially if the guys you were having sex with were a lot older. Of course, out in real life, it certainly could, and everyone knew it, but they weren't supposed to admit that on television.
90210 became very popular, at which point they toned it way down and I stopped watching it.
The episode that made me realize that this show was no longer worth my time was one with Emily Valentine. She was Brendan's psycho stalker ex-girlfriend, who started out as bad news and spiraled down into more and more insane behavior. Finally she doused a homecoming float with gasoline and sat on it with a lighter. Dun-dun-duuuhhh!
And then not only did she decide not to make Emily Flambé, but she proceeded to launch into this lengthy analysis of why she was so unstable. (Her family moved a lot.)
OK. Say, you're emotionally unstable. You've been unstable for quite a while. Your instability is making you screw things up, and which is making you even crazier. Finally you get ready to commit suicide by setting yourself on fire.
You are not in a position to analyze why you are acting this way, OK? You are too unwell. You might understand intellectually that what you are doing is harmful, but you don't understand the forces that drive you to harm yourself, at least not in a helpful way. Maybe after therapy and perhaps medication, and once you get some distance on events, maybe then you can sort out all the whys and wherefores--but not in the red-hot moment.
It's contrivance. In 90210 it was that safe, pedagogical approach to teen fare--you can't have someone do harmful things without turning it into a "The More You Know" moment, otherwise all the parents' groups will accuse you of glorifying bad behavior. I recently read a novel where, despite the fact that it was set in the 19th century, all the characters exposit (constantly) about their family and their interactions exactly the way people who have been through a lot of therapy in the 21st century do. That's also contrivance--historically-inaccurate contrivance.
These kinds of contrivances suck away all the drama. It's not just that having all your characters prattle on about how their father and their brother and their mother and their sister and their cousin and their brother-in-law and their dog all interact now and have interacted at every point in the past is dull--although it's certainly that. It's that Emily Valentine was all better. She was 100% fine--no need to worry about her any more! She's never going to do anything bad again! Please don't care! It's very, very difficult to relate to someone who has a mental-health hotline in their head that will magically call them at any stressful moment in their life and make sure they never, ever do the wrong thing.
Which is not the same as saying a character can't grow and become more stable--but it's a process, and circumstances have to be right. In Lois McMasters Bujold's Vorkosigan Saga, Mark Vorkosigan does this pretty convincingly: He is given a very robust support network, it takes a lot of time, and he's never without his hang-ups. The very fragility and imperfection of his recovery is emotionally engaging. He isn't just bonked on the head by the Contrivance Fairy's wand and magically made all better the way Emily Valentine was.