It's called thieving, stealing, taking what's not yours. Is that really what you want? Your life to go?
It's not stealing because the owner is not losing anything. If they couldn't pirate, pirates would just not have the thing rather than buy it. Basically, if you're not losing revenue because of it, you might as well have more people enjoy your work. And because of word-of-mouth, pirating may actually INCREASE sales.
That said, I don't pirate games or music (they're all on YouTube anyway.)