I can’t analyze the police half, but the courtroom half is pretty over theatricalized, and also dumbed down. The “lawyers” on the show often use terms that don’t really mean anything like “badgering” instead of something more precise, such as “leading a witness during direct examination”. And there are a lot of objections that are made under the wrong terms, such as simply saying “prejudicial” instead of the (often better/more winable) objection, “more prejudicial than probative”. They also do really stupid things that real attorneys worth a lick never do, like refer to the defendant as “my client” or shout “withdrawn” every five seconds.
When you say “my client” it reminds the jury that you have a side, and you’re just there to win your case and get paid. As a counselor on either side, you want the jury to see you as in impartial person who’s just there to tell them what happened and let them decide; you don’t want to remind them constantly how biased you really are. As far as shouting “withdrawn” you wouldn’t want to do that, because it looks like you’ve asked a question that you know is inadmissible, so there would be no point in arguing the objection. It looks like you either don’t know what you’re doing as an officer of the court, or that you’re purposefully trying to break the rules of evidence. Those both look very bad to judges.
Probably the most legally inaccurate part of the courtroom side is the endless monologues of counsel testifying, by that I mean lawyers saying things while a witness is on the stand. This is against the rules of evidence, and thus illegal. It is the easiest objection in the world to make and win, and yet no one on those shows EVER does. The lawyers have their chance to talk during opening and closing statements, and other than that, everything they say (besides objections and housekeeping) should be a question. There is absolutely no place for the kind of statements McCoy and the others are always making, like, “You had access to the car. You had the keys to the building. The knife was found in your possession.” blah blah blah. All that is testimony by the lawyer, and it’s all against the rules of evidence.