In a small farmland, once upon a time, a boy and a girl were playing together. The boy had a collection of marbles and the girl had some sweets with her. After looking at them for a while, the boy couldn't resist the temptation of sweets, and had to ask the girl if she will give him all her sweets in exchange for his marbles.
Well, to his surprise, the girl readily agreed!
Smart -- that's what he thought he was -- so he hid the biggest and the most beautiful marble aside and gave the rest to the girl.
On the other side, the girl gave kept his promise and gave him all her sweets as promised. That night, the girl slept peacefully as always, but the boy couldn't close his eyes. He kept wondering if the girl had hidden some sweets from him the way he had hidden his best marble!
If you don't give your hundred percent in a relationship, you'll always keep doubting if the other person has given his/her hundred percent. This is applicable for any relationship be it at home or work -- give your hundred percent to everything you do and sleep peacefully.