One of the most critical processes in managing projects are those addressing project risks. Some writers go so far as to call risk managent 'project management for adults'. The implication being that if you’re not doing risk management in your project, then you’re just a kid, you haven’t grown up yet, and have no place among grown-ups (I agree with this view, by the way).
When asked what risk is, quite a few will give an answer that goes something like: 'a risk anything that can go wrong.' In this view, a risk is something that can go wrong, and therefore risk management is about addressing those things that can go wrong.
But there is another, less commonly known, view of risk. In this view, risk is something uncertain that may affect the project. Not something necessarily bad, but something uncertain.
Let's suppose you are planning a picnic for tomorrow. Being an adult, you have prepared a risk management plan (your picnics may be boring, but they are predictable). You have an entry for weather in your risk plan. In the first view of risk, you look at the weather and look for something that could 'go wrong' that could negatively affect your picnic. Is it going to rain tomorrow? If there's a chance of rain, what can we do to mitigate the effects of this rain on the picnic? Perhaps bring an umbrella. Perhaps plan to hold the picnic nearby an accessible shelter, to make escaping from the rain easier.
In the second view, we look at the weather not as something that is the harbinger of something that can go wrong, but simply something uncertain. So there's a 50% chance of rain. Let's prepare for that eventuality. But there's also a 50% chance of no rain. Let's also prepare for that happy eventuality as well -- perhaps plan to go to a place with a nicer view if the weather clears up.
With this second view, risk is not simply viewed as about bad circumstances that can happen, but simply about all uncertain circumstances. Circumstances which can indeed turn out bad (and whose effects we should be ready to address), but which can also turn out good (which we should be ready to take advantage of).
In the first view, we simply prepared ourselves for the worst. But in the second view, we also prepared ourselves for the best.