You should not limit yourself to one side, as it is smarter to assume all kinds of forms.
What I said, a person becomes a thinker first and then becomes a doer, that is the ideal way to approach. But some might get stuck in the thinking phase unable to execute the decision. This needs some help from other people or their own self to push themselves forward.
If you do without thinking you will face a number of loopholes which you have to close early and take rash decisions, most of the time they will end up ugly.
Either way, think first before you do.