I, too, have been guilty of this. When we lived in Mexico City, my next-door neighbor was a young television personality. We would chat from time to time, and he even mentioned that he listened to our radio program occasionally. But I didn't share the Gospel with him. I thought, "He seems completely immune to the problems of life."
Eventually, though, my neighbor's situation changed. The joy seemed to have left his face. He and his wife started driving separate cars to work. I could tell their marriage was souring, and I felt the need to talk with him, but I didn't want to meddle in his life. I went about my business and headed off for an evangelistic crusade in Peru. After all, that was the polite thing to do.
When I returned home, I learned my neighbor had killed himself. I was heartbroken. I knew I should have gone to him and persuaded him to repent and follow Jesus Christ. But because of false courtesy -- because I followed a social norm -- I didn't do it.
It's very convenient to make excuses for not persuading others to follow Christ. We may say we don't want to be overbearing or offensive. We may think we can't possibly witness to someone because he or she will become angry. But often the opposite is true.
Illustration taken from: Luis Palau's book, How to Renew Your Spiritual Passion, Discovery House, 1995.