You cant really begin to appreciate life until it has knocked you down a few times. You cant really begin to appreciate love until your heart has been broken. And you cant really begin to appreciate happiness until you've known sadness. Once you've walked through the valley, the view from the mountain top is breath taking.
The longer you have to wait for something, the more you will appreciate it when it finally arrives. The harder you have to fight for something, the more priceless it will become once you achieve it. And the more pain you have to endure on your journey, the sweeter the arrival at your destination. All good things are worth waiting for and worth fighting for.