Are the police really this bad?

I recently broke my hip and have had to sit on the couch for weeks after surgery. It's allowed me a lot of tv watching and I have watched lots of Dateline. One thing that has struck me is how wrong the police are in so many episodes. They focus on one person after an initial investigation and once they start focusing on their suspect, they tend to ignore any evidence that doesn't support their theory. Sometimes it's easy to see why they think it's a certain person, but other times it's baffling they ignore so much evidence that doesn't support their suspect being guilty. It's gotten me to question, is this just bc we are only seeing episodes that are tough to solve, or do the police routinely do this and jump to a conclusion and never stray until the evidence is just too overwhelming to ignore. I think police have a tough job and they normally do a good job, but I can't help but wonder after watching all these episodes how many people are wrongfully in jail. I don't care about politics and trying to get into a politically discussion with this, but I do care about justice. And if all you do is watch this show, it has to make you wonder if it's been done. My question is this show just a small part what happens in real life, and not an accurate portrayal of how good a job the criminal justice system works(they do get it right a lot) , or is it showing us that we are putting way too many wrong people in jail based on police focusing on the wrong people? I don't know the answer, but watching so much Dateline has made me wonder.