I simply don't have enough free time--that which is outside of responsibilities and obligations to work, family, or friends--for all my hobbies. I'm sure many people feel the same way. Precisely why anytime I hear someone proclaim that they're bored, I want to smack 'em upside the back of their head.
I'll never get anywhere near being satisfied with how many books I've read, how often I was able to play guitar, how many great films I was able to take in, how many old NES/SNES/Genesis/PSX games I played, or how much I was able to learn about FOSS/GNU/Linux/computers. And don't even get me started on travels and cultural experiences! Alas, there's just not enough time. How can people ever be bored? Astounding.