by the logic of the OP, why do all of those miserable fuckers in dire straits have a right to be unhappy when there's so much awesome stuff in the world?
what applies to one doesn't always apply to the other... I've been through some tough shit in my life and have hit points where I genuinely believed that the world would be a better place without me in it if I could find a way to off myself and make it look like an accident to insurance investigators. I'd had some pretty terrible things happen to lead me there... did I think that other people should feel miserable just because I was? no... I wanted them to go on with their lives and be happy and I think that a lot of people who've genuinely hit such a point think the same way from those I've discussed it with... why should my unhappiness cloud everyone else's lives?
live your own life... it's really all that you can do... be happy if you're happy- you owe it to yourself and those who aren't