In untempered melted chocolate, the fat crystals (specifically the beta crystals) have not been aligned, leading to some undesirable qualities. When that chocolate is used for dipping, say, a truffle, you get a dull finish, a wimpy, bendy bite, and a general air of “I-just-melted-some-chocolate-to-dip-stuff-in-leave-me-alone” hanging about. Tempering the chocolate brings those fat crystals into line, and the heavens open and the angels sing. Those chocolate dipped truffles are show-worthy, glossy, smooth, with a sharp mouth-pleasing snap when bitten. Tempering gets you professional-level results.