"We have to be proactive about this!"
The implication, of course, is that we have to get ahead of the situation, put a plan in place, and stop simply reacting to what's going on. If you're reacting, you're always going to be just a bit late. If you're proactive, though, you can anticipate things that are going to come up and have an answer or a solution for them. Laudable ideas, all of them!
But... (there's always a but)
There is a time to be reactive. Being purely proactive means you have a plan, and you will stick to that plan. Since we're note all great prognosticators of future events, our plan is likely to need some modifications as we move forward. We're going to have to react to events as they occur, making ourselves a bit reactive (gasp!).
This is not a call to stop planning or to stop being proactive. There is immense value in having answers ready when you need them because you've proactively gone out to get them. Your clients will feel much more comfortable if you can answer their questions and concerns readily because you've been proactive. Your colleagues and subordinates will be glad you anticipated the pending lab power outage and didn't leave them with a lot of half-built code and half-run tests. You'll be better able to handle crises when you've considered them and what you have to do beforehand.
Be proactive in your overall plan. Be reactive in the details.
Being proactive involves thinking about the future likelihood of events and preparing for them today. As those events unfold, though, keep looking and react to them. Your earlier preparation means you have the big pieces in place. Your reaction will make sure those pieces are tweaked to work as the situation actually warrants, and not trying to make something not quite right work.
So please, be proactive. But be reactive, too. The combination is what will get you ahead.