Spike really has no interest in answering Aziraphale's first question. He's always enjoyed the world, even before he regained his soul. Appreciating is another thing entirely. Thankfully, he's saved from answering because the angel goes on to mention that he averted the apocalypse.

"You must be from a different dimension. Where I'm from it was me and my friends that did that." He considers for a moment. There was the time he died. That was definitely apocalypse-averting, but there have been a few other times that have come close. "More than once. Depends what you could call an end of the world situation."