by definition is controlling a situation by causing something to happen rather than waiting to respond to it after it happens. In my world, this is a must. Not only do you have a better control, but if your proactivity actions do not change your situation in your favor, you are still in a better position to handle what the situation was.
Proactivity goes hand in hand with self responsibility. You are responsible for what happens to you, no matter what. It may not be your fault, but it’s your problem. You are responsible. Just take care of it. Try to prevent it from happening again.
So maybe you don’t always have control with everything that happens to you out there. You can’t. Too many idiots. Or worse-people who actually are TRYING to screw you. But being proactive will give you as much of a head’s up on your situation as you can get and what can be done to turn it in your favor. Or, worst case scenario if someone/something is trying to take advantage of you, being proactive(asking lots of questions, for example)
Bottom line: proactivity means being aware of what you are doing, what situations you are in, what the possible outcomes are, and turning them to your favor or getting the hell out of there.