It's simply an attempt to establish the baseline to the speaker's liking. For instance, someone who doesn't like skydiving: "why would you jump out of a perfect

It's simply an attempt to establish the baseline to the speaker's liking. For instance, someone who doesn't like skydiving: "why would you jump out of a perfectly good airplane?" Let's start with the fact that there are no "perfectly good" airplanes, then we can debate the wisdom of free falling from 3Km.