Top Ten: problems you prevented

Heroes who sweep in to handle a crisis get plenty of attention and praise, but it's an often-noted irony that you rarely get credit for preventing a crisis. Nothing happens; it's a non-event; and often no one but you knows what you did to keep things from going off the rails.

What are ten problems (large or small) that you prevented, crises that you averted, or disasters that didn't happen because you were there to stop them?

You might have to dig through your memories to answer this question, but it's worth taking the time to give yourself another silent round of applause. Did your well-timed advice keep a friend from making an expensive mistake? Did you recognize someone's symptoms and help steer them towards getting appropriate medical care? Did you talk someone out of taking rash action in a moment of anger or desperation? Were you at the right place at the right time to hold things together when they otherwise would have fallen apart?