Plato.
One day, Plato asked his teacher, "What is love? How can I find it?" His teacher answered, "There is a vast wheat field in front. Walk forward without turning back, and pick only one stalk. If you find the most magnificent stalk, then you have found love." Plato walked forward, and before long, he returned with empty hands,having picked nothing. His teacher asked, "Why did you not pick any stalk?" Plato answered, "Because I could only pick once, and yet I could not turn back. I did find the most magnificent stalk, but did not know if there were any better ones ahead, so I did not pick it. As I walked further, the stalks that I saw were not as good as the earlier one, so I did not pick any in the end. His teacher then said, "And that is love."