It doesn't seem like it. Body cam and dash cam videos show it. Body cam also shows a very violent demographic in America who thought it was a good idea to record their interaction.
You watch too many YouTube videos.
You should try watching On Patrol Live. You'd have a very much more accurate understanding of what police officers do and why they do it. Police are not violent, they're scared. That's right, they're scared. They are trained to be scared to death that they aren't going to get to go home to their families that evening. If you think you've seen a lot of police officers being violent, you wouldn't know how to handle the videos police officers are exposed to on a regular basis where they're shown their colleges being shot in the face or stabbed or God knows what all. They fed a steady diet of other police officers who let their guard down for one second and paid for it with severe career ending injuries if not their lives. This is why they treat every firearm as if it going to leap out of the glove box on its own and start firing itself at their partner. They overly paranoid because paranoid police officers get to go home at the end of their shift. That's not their fault. That's the society we live in and that's the super-violent portion of it the police officers deal with day after day.
Sure. Officers rattle off a list of things that someone nervous will do and say it is suspicious. A psychopath, a real one, will show none of those behaviors.
Which it another things they're trained to look for. What they're trained to look for is normal behavior. They know what normal people do in nearly any situation, particularly stressful ones. The behavior at a car crash, for example, can be anything from confusion, to sobbing to laughter. Pretty nearly any sort of overt emotional reaction is "normal". What is not normal is no emotion at all or sticking around but trying not to be noticed. The guy doing nothing but impassively sticking around but avoiding being seen is the guy that's going to catch a police officer's eye precisely because that is not a normal stress response.
The majority of police officers spend their day in the worst parts of town, doing things that ruin the day for worst people in town. Most of the time they don't give normal people like you and me a second thought. They're just as happy to let us get on with our lives so they can deal with someone doing something they're not supposed to be doing. In other words, police officers do not need to go looking for people to give a hard time too. Bad guys are all over the place.
There are bad apples - no doubt! Any video that anyone can find of a bad apple being bad is posted on YouTube because those are those are the one's that get watched. Police officers doing their regular job is quite boring to watch. Not only that but when you watch one of those videos, YouTube is designed to feed you more of the same. More importantly, the left is at war with the rule of law in the country (around the world really). One of their most effective tactics is to post videos of police doing their job badly, which you watch and end up thinking that police are nothing but a violent demographic! You've done nothing but buy into the left's propaganda.