Going with the flow is great EXCEPT when you see something wrong with the flow. If that happens I find that I'll try and find away around the flow. Barring that, I'll fight the flow. My problem is once I reach that point, I obsess until I either change things or find I can't take it any further.
Regarding decision making, I think the trick is learn to identify which decisions are worth more consideration and which are not. The rule of thumb is gauging the downside of a bad decision. If the decision's worse case scenario isn't life altering and can't be taken back, then I feel I can go with more of a gut instinct decision rather than stressing over it for a long time. I guess I've learned to do are quick upside/downside evaluations of types of decisions. All you need to know is if you can't come up with really bad downside almost immediately, it usually sticks the amount of consideration way down the scale.