Love is a lot like Pokemon. You're going to get a starter and it's going to mean a lot to you. But throughout the game you'll run into plenty of other Pokemon.
Some you'll use a pokeball to catch, others a great ball or even an ultra ball. You're going to run into a couple of rare Pokemon and even a few legendary Pokemon.
You might catch them and you might not, but no matter what you do--save your master ball. Save your master ball for that one Pokemon.
That one Pokemon that is truly legendary.