My mother was very ill with terminal cancer she was given a few weeks to live, but she started speaking the word praying healing scriptures and it didn't happen overnight, but in time she got better and she's healthy today. Why did God heal my mother and not someone else's I don't know. I just know I'd rather die believing.
Keep in mind, hurting people often hurt other people as a result of their own pain. If somebody is rude and inconsiderate, you can almost be certain that they have some unresolved issues inside. They have some major problems, anger, resentment, or some heartache they are trying to cope with or overcome. The last thing they need is for you to make matters worse by responding angrily.