(I am waiting for the resident gun nut to make an appearance and bring up the 2nd amendment - hehehe).
I'm not going to go political and 2A here, but the gun handling on most every TV show or movie is horrible. The way people repeatedly pump the shotgun, they'd be out of ammo before they first pull the trigger. Every pistol when handled makes some sort of cocking noise, without actually racking the slide. Why do so many cops carry around a gun without a round in the chamber, so that they have to rack the slide before going into action? "Ha, I saw the safety was on, so I could...." But that Glock doesn't have a safety. And not all black handguns are Glocks. And getting shot with a handgun, one time, does not knock you across the room and instantly kill you. And on and on and on....
Cop shows in general - they sure have access to a lot of DNA databases, including some that don't exist, like the military. What real life cop office space is so bright, so roomy, so modern as what you see in half the shows? Barney Miller probably came closest to reality.