Heh, maybe I'm gloomy, but I definitely haven't given up on life ;)

Why would a Big Truth be worth it if you only got to learn it but not actually *act* on it

Because you'd know. You wouldn't have to end your life without knowing! I'm already bothered by the fact that I'll never know how the universe came to be, or to where Space is expanding. If I got to know at least one of the big things, I'd die happy. So, I suppose it all comes down to curiosity, in the end...