One time a while ago, a cat found a baby iguana on the street. He wanted to keep him. He thought the iguana might die on the street if he didn't take care of it himself. The cat thought himself responsible enough to keep and take care of it. Just as he was going to grab him, yoink and he was gone! The iguana had vanished. He looked for the iguana everywhere. As the hours past, the cat became very worried. The cat pounced and pounced and pounced everywhere around asking animals where the iguana was. But iguana was nowhere to be found. Then, he heard a voice calling out to him, "Cat, don't you know, responsible or not, you can't keep everything you want?". 
You can not keep everything you want. 