When I consider the "thinkers" in the play, I immediately think of Hamlet and Ophelia, and when I think of the "doers," Claudius and Laertes come to mind. Ophelia seems to spend so much time considering Hamlet's horrible behavior toward her and their one-time love for one another, then the death of her father at Hamlet's hands that she simply goes mad. Obviously, Hamlet spends a very long time contemplating how to best achieve his revenge on his uncle, and lots of people die during this time, potentially the result of his hesitation and overthinking. His behavior shows that inaction can be as destructive as rash action.

Claudius and Laertes certainly do act quickly on their ideas, but nothing really works out for them the way they think it will. Gertrude drinks the wine that Claudius poisoned and intended for Hamlet to drink, and Laertes is nicked with his own poisoned rapier with which he intended to kill Hamlet. They are "doers," but they both ended up dead, having done pretty dastardly and dishonorable things.

Personally, I'm more of a thinker, and though Hamlet and Ophelia do not exactly have happy endings, I'd rather be a thinker. I'd prefer to overthink things and not move very quickly than to be in a rush to act and make fatal mistakes as Claudius and Laertes do.