I recently helped some friends move into their new home. Loading a moving truck is often a delicate process. You need to put everything in the right place, stacking items appropriately to optimally use the space of the truck. As we loaded items into the truck, we made quick decisions about where items would go based on the idea that we had plenty of space for the amount of furniture, appliances, and other things we needed to load.
About halfway through the loading process, we realized we had more stuff than we had thought. We also realized how big the remaining items were.