Cos it doesn't exist. No one is truly happy all the time. So when you find yourself feeling the tiniest bit of happiness, you better fucking hold on to it by savouring every fucking moment till the next thing brings you down. Be it yourself, other people, your surroundings or whatever.
Why is it this way, you ask? Cos sometimes, sometimes the world plain sucks. The universe plain sucks. And it just wants to fuck with you. You can quote me on that wtf.
Sometimes, all the beautiful quotes aren't enough.
Sometimes, even beautiful, inspiring words get it wrong.