John Ruskin said this quote

the true knowledge is disciplined and tested knowledge,—not the first thought that comes, so the true passion is disciplined and tested passion,—not the first passion that comes. The first that come are the vain, the false, the treacherous; if you yield to them they will lead you wildly and far, in vain pursuit, in hollow enthusiasm, till you have no true purpose and no true passion left. Not that any feeling possible to humanity is in itself wrong, but only wrong when undisciplined.