Why curve?

Why not just be upfront about it? I truly believe honesty is always the best approach. But in most cases unnecessary. Let’s say you agreed to meet someone new, but later on someone else you’ve already conquered invites you to share their company. After weighing your options you would most likely choose to chase your new prey and keep the other as plan B. However if you get lucky from your new prospect, it’s conventional to curve your plan B. This spares feelings ensuring that the person will still remain an option for future occasions. Being blunt enough to admit you didn’t call them back because you got what you wanted elsewhere is only going to push the person away; they’re no longer assured gratification.