Its usually one that makes sense and has some kind of emotion that I like
In Figure 5.8 (a), the demand curve is drawn as highly inelastic

and we watch it as it flows, ever singing, ever whispering, out to meet its king, the seatill our voices die away in silence, and the pipes go outtill we, common-place, everyday young men enough, feel strangely full of thoughts, half sad, half sweet, and do not care or want to speaktill we laugh, and, rising, knock the ashes from our burnt-out pipes, and say Good-night, and, lulled by the lapping water and the rustling trees, we fall asleep beneath the great, still stars, and dream that the world is young againyoung and sweet as she used to be ere the centuries of fret and care had furrowed her fair face, ere her childrens sins and follies had made old her loving heartsweet as she was in those bygone days when, a new-made mother, she nursed us, her children, upon her own deep breastere the wiles of painted civilization had lured us away from her fond arms, and the poisoned sneers of artificiality had made us ashamed of the simple life we led with her, and the simple, stately home where mankind was born so many thousands years ago

via repeated measurement occasions (Fig
This consistency across batches demonstrates reliable manufacturing quality control