There was once a frog who lived in a pond next to an abandoned palace. Occasionally a traveling witch would come and stay in the palace. One day, the frog decided to go and have a look at the abandoned palace. He hopped over and jumped up to an old window frame. Instead of being filled with glass, the window frame was filled with what looked like a soap bubble. The frog was amused and wanted to pop the bubble by jumping through it. However, this was no soap bubble; it was the remains of a magic potion. As the frog jumped through it he found himself entering a very different place. It looked like he was entering a very rich person's house. The place smelt nice and was heated. But that didn't last very long: a dog spotted the frog and was about to catch him. Fortunately, with three great leaps, the frog managed to jump back out of the window… only to find himself now in a wonderful pond, full of frogs and toads of great beauty. The pond had an abundance of flies, and the frogs and toads croaked happily all day long. Our frog was neither handsome nor ugly; he was just pretty normal looking. This meant he wasn't greatly welcomed by the other frogs and toads, but he was enjoying himself so much that this didn't matter much to him. He lived there for many days, but one night a group of toads who were sick of the frog's common appearance, grabbed him while sleeping and threw him back through the window. The frog woke up in a dark, dilapidated, cold and uncomfortable bedroom. There was a young boy there, and the boy welcomed the frog with great happiness. Soon the boy and the frog were inseparable companions. The boy looked after him as best he could; he even caught flies for the frog. However, the frog couldn't help thinking about all the comforts of the wonderful pond he had experienced. One night, when the cold was worsening, and the firewood had run out, the frog hopped to the window and leapt out. He came out at the north pole! The frog felt like he was dying of cold, so he quickly jumped back through the window. This time he found himself in a desert, and when he again jumped through the window he was back among the arctic snows. It didn't matter how many times he jumped back and forth, he would always come out at either the north pole or the desert. While he was changing from one place to the other he remembered his good master, the poor boy, and how he, the frog, had been so ungrateful to the boy, and so loving of his own comfort, and how this had meant him ending up in this situation, half dead from hunger, and jumping from the worst of cold to the most searing heat. 
We should focus more on what we have than what we don't, as senseless ambition can lead to us losing everything. 