Common sense is doing what we “should” do not what we could do. It is what “everyone” else would do. An example is; if your thirsty find a water fountain or if a baby pukes on you then wipe it up, clean your clothes and have a shower…at some point during the day, because anyone living with a baby knows that the ten minute shower is a luxury that only comes at special, unplanned points during the day, like an impromptu nap. This just goes to show that common sense is slightly different depending on life circumstances, culture and other factors. However in summary common sense is comforting and sometimes we make these decisions without even realizing it, like a zombie. You do what your meant to do, you don’t even think about your choices because you don’t need it, you already know what you are going to do.