I propose that ruminating is the one thing I do most of all. I think, and think and think, thus, I ruminate. I would say that over thinking helps you come to the end point of a problem faster, but, it may also hinder, or even disable your thought patterns, or even you. It is a dangerous thing; overthinking. Sometimes, by all means, you could be right, but also, you could be very far from the truth.
The problem with rumination is the struggle to find balance; the balance between thinking and letting things go. For me, I think the lines are still very much blurred… but I do try.