Share of Cost, Be kind to your teeth
Think twice before using your teeth as tools. Many people get into a bad habit of opening a stubborn chip bag or holding objects in their mouth however doing so can cause chipped or cracked teeth.
You do not live in the Stone Age, so there is really no excuse to use your teeth to open a bottle of beer, the bottle opener was made for that. Tools are easier to replace than your teeth, which were really meant to last you a lifetime.