During my previous life as a police officer, I was one of a very small group of people that have the right to lay hands on a fellow citizen, under circumstances that are governed by the law. This action is in effect an assault, the application of force to the person of another without their consent. It is only particular circumstances that make this act lawful.
As a police officer I always felt, and still believe, that if you ever got used to this and took it for granted, you had lost something. On a slightly different tack, colleagues would often say that they were never bothered by death and that they were `used` to dealing with death and its detritis. I never was. It was familiar to me, death in all its forms, be that violent or peaceful, from babies to the very old, but I never got used to it in over 30 years of service. I got used to dealing with it, but I never became indifferent to it.
The application of force is a normal part of the job. It can be exhausting. I always felt that most people never realised that. These people found out.