Unlike most entries, which focus on the person's not realizing that they are being used - the true definition of a tool is someone who thoughtlessly, but willfully, follows someone else's orders, thus making themselves a tool of their leader.
Some douchebag cop who gives you a ticket even though you have a very good reason why you don't deserve it, a reason any normal, feeling person would recognize but that the tool in question doesn't feel like acknowledging because he or she is just being a f***ing tool!
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