Each person we come in contact with will react differently. One must use their people skills and determine whether or not this person is ready to hear it or not.
I had a person come into my place of business, and sat down and decided to witness to one of my employees. The employee was in sales, and nothing was going on, so I let them talk. The witness must have been nearing 80. I could have slammed the witnesses down one side and up the other. But I felt it was not worth it in this case. This man had been a witness his entire life. He knew nothing else. He was a nice guy, and very sincere.
Now you bring me an asshole witness, who thinks his shit don't stink, and there is quite a different scenerio.