Very true. It’s very, very, very important that you are attached to your characters. If you want them to do well, then there is a chance your audience will want the same thing.
But then you have to ask “what is the worst thing that could happen to them? What is the thing they fear the most?” And even when you come up with it, you have to ask why is that so bad? Even when you think you’ve come up with it, you really have to ask “no, really, why is that so bad?”
“Well, they’d be dead!”
“Everyone dies, why is it so bad that they die?”
“Well, his children will be taken by his wife’s new husband who will molest them.” (Pretty bad, hunh?)
“At least they aren’t dead. So why would that be so bad?”
“Are you crazy?”
The point is that this is fiction, so none of this is really happening, so the audience can step out of it at any point, so it really has to get bad from their perspective not just the characters.
On top of that, you have to figure out what is the worst thing for the character to do. What is the darkest thing they would have to do to avoid the worst thing that could happen to them. Drama is about actions and choices, not just terrible events.