Just thought I'd point out a couple of differences between my experience and the post here.

1) I always take a long gun (shotgun and/or rifle) and a heavy vest with me. Those things stay in my car unless I'm going to a call where I might need them. I take out the long gun on any call where there is credible information that the suspect has a gun, and I put on the vest if there's a good chance the suspect has a rifle (regular body armor does not protect against rifle rounds).

2) Most cops I know aren't rude, they're just very direct. We have a job to do, and while part of our job is helping mediate disputes, we frankly don't care that you're arguing with your neighbor over where he places his garbage cans, or other petty complaints. Why? Because (a) you're both grown ups and should be able to figure out a solution without us and (b) while I'm helping you learn a lesson you should have figured out in kindergarten, I'm not on the street looking for the actual criminals so they don't murder you, rape your kids, etc. So, yes, we're going to be direct and to the point so we can solve your problem, make you reconsider calling us for stupid stuff, and get back to hunting evil-doers as quickly as possible.

3) The seatbelt one gets me. Sure, it's your business if you don't want to wear one. But it's my business, too because I'm the one that has to tell your family that you died. I also have to shut down the road and do a huge investigation, using up hundreds of man-hours worth of resources and inconveniencing countless people who will now be stuck in traffic. And, if there's anybody else in the car with you, you are a safety hazard to them. Ever seen what happens to an unrestrained person during a roll-over? If there's anybody else in the car with you, your body will bludgeon them until the car stops or you get ejected.

4) You touched on a lot of really good use of force issues. Here in the US, we don't shoot to kill, we "shoot to stop the threat." Frequently, the threat stops when they are dead, but our intent isn't to "kill," as that would make us executioners. Our intent is to "stop the person's immediately violent actions." There are three ways a person can be stopped when shot:
(a) psychological-- the pain/ fear caused by the wound
(b) neurological-- the brain/spine is damaged, causing immediate unconsciousness or paralysis
c) hemorrhagic-- the blood vessels are ruptured, causing massive bleeding, leading to unconsciousness.
We usually aim center of mass to accomplish this because all three types of stops overlap in this area.
On top of all this, in the US, six out of seven people who are shot with a handgun survive. So getting shot by a cop is not an automatic death.

5) Some jurisdictions have quotas, from what I've been told. However, in my state (California), quotas are illegal. Our bosses do ask us to bring in a few tickets, depending on how busy we are, and we have areas and violations that we focus our attention on. These are usually associated with high instances of traffic collisions and/or citizen complaints, all of which are tracked in our stats system.

Thanks again, bro. Good stuff here. Keep it up!