In this very famous scene, which has been immortalized by phrases such as "tilting a windmills" and in art by Pablo Picasso, Don Quixote mistakes some windmills for giants and, in true knightly style, rushes at the windmills with his spear in hand. When he realizes he attacked a windmill, and not a giant, he blames a magician and says the magician turned the giants into windmills. This scene resonates with us because many of time people fight battles against the wrong enemy. For instance, they assume that they should battle their boss for some decision when instead it was the bosses boss who actually made the decision. Fighting the wrong person means wasting your time and energy on the wrong target. Since this is such a common human foible, the expression "tilting at windmills", which is an allusion to "Don Quixote", has become synonymous with wasting your time and energy on the wrong target.