student: teacher, what is love?
teacher: to know what is love, go to the corn field over there. pick the largest corn and give it to me.

the catch: u can only look at all the corns once. u're not allowed to turn back.

the student went to the corn field. after walking for awhile, he saw a big corn. but he thought "there should be a bigger one in front". true enough, there's a corn that is bigger than the previous one. then, he thought again "there must be a bigger corn further up" and as he have thought, there really is a larger corn. he thought again "this corn is big but i may find a bigger one". he continued searching. after covering more than half of the corn field, there isn't a corn that seem bigger than the previous corn. he went back to the teacher empty handed.

the teacher told him. this is love. u keep searching for a better one and u missed out on your chance. so we have to cherish all our loved ones and not until when we lose them.