Is it possible to think too much?

I often wonder whether the comment made to me that I 'think too much' holds any weight at all or not.
In the one hand, I can very easily be lead down long, windy and very pointless paths, where I come out none the wiser, but a lot more confused. On the other hand, these paths may eventually lead to some new thinking - if not for the rest of the world, then even just for me - and this could be a life-changing walk.

I guess getting tangled up in thoughts, in itself, isn't a bad thing - but its whether getting tangled up prevents you from being alive, strangling the life potential out of you.

Where - if at all - should one draw the line and say, "Okay, time to stop thinking now and just focus, albeit ignorantly, at the life in front of me"?