This is a stupid question. Been playing FS for a while but I still don't get the trick. I've been seeing from neighbors that they're able to stock up clothes while blocking their doors for days and when they open their boutiques again, their clothes won't sell too fast. I tried blocking my door for 4 hours and when I re-opened my boutique, everything on my shop got sold. Are there ways in order to avoid quick sale? Help is very much appreciated!