What is your biggest fear?

I have many fears, some worse than others, some more reasonable than others. I can't cross a bridge without the thought coming to mind that if I wreck on the bridge or if the bridge fails, I will drown. Not a very reasonable fear. Learning to swim helped a little but drowning is one of my fears. I had a fear of heights until I went to boot camp, I was at the top of the repelling tower at Parris Island and the Drill Instructor asked if I was afraid. I responded, "Yes Sir", he said "Well Private, just think of it this way, in a few seconds, there will be one more thing in this world you aren't afraid of, now jump." And I jumped, rappelled down to the ground and he was right. For me I have to do something at least to some degree to overcome it. If I were afraid of the dark, I would have to confront the dark to be unafraid.