You need to wash your hands, because there are always germs on them. You can’t see them, but they are there and these germs will spread to other people. If some one has a cold or flu and opens a door and you touch that same door knob you get those germs on your hands. If you wash your hands you will not catch that person’s clod or flu and you will stay healthy. But, if you do not wash your hands you will end up with what ever that person had.