If you take a closer look at the lid of a coffee cup, you’ll see a little hole on it. Such holes act as insulators for the heat from the beverage. The hot steam has to escape so that it can’t dislodge the lid. If you notice this hole, it means that it’s impossible to get a burn.

Small buttons on lids also have a purpose. In fast food restaurants, soft drinks are made in advance and covered with lids to keep beverages hot. These buttons help restaurant workers understand what’s in a cup, whether it’s tea, coffee, or cappuccino. Near each button, there’s a name of a drink and if it’s pushed, there’s no need to check what’s inside.

13 Everyday Things We Didn’t Think Had a Purpose