I was with a companion at the time who was... difficult. I could tell that the other missionaries weren't real excited to have us tag along, so after a couple of minutes I made our excuses and we went our way.
One of the companionships called me that night. A few minutes after we left, a limo pulled up, and out stepped Billy Joel and Christie Brinkley (who were married at the time). I missed out on meeting my childhood crush because I was trying to not discomfort some fellow missionaries.
Given that Billy and Christie later split, there is a definite chance that were it not for that, Christie and I would be together today.