One day a woodcutter was passing through the forest. At one place, he saw an eagle trapper in a trap placed there by a hunter. Woodcutter felt pity toward that eagle. He checked around to see if hunter was near by and then seeing no one he ran toward trapped eagle and freed him from that trap. Eagle thanked woodcutter and flew away. Some days later, woodcutter was sitting on a mound and eating food, suddenly an eagle came from somewhere and snatched his food, flew away with it and sat on a near by tree. In attempt to save his food, woodcutter lost his balance and fell down from that mound. When woodcutter looked at that eagle, he recognized him and realized it was same eagle whom he had saved previously. Woodcutter got angry thinking that even when he helped eagle, eagle snatched his food. Woodcutter started cursing that eagle. Just then eagle said, "Mister, I saw a poisonous snake behind you and it was about to bite you that's why I came and snatched your food and flew away.and because of that you fell from that mound and snake was not able to bite you."When woodcutter looked behind, he saw that snake, he realized what eagle said was true and thanked him for saving his life. First, if you help others, then they will also help you. 
Second, many times in life we prejudge things we experience in life because they are not packaged as we expect them to be due to this we misunderstanding others. 