You're Not Paying Attention to the Color of Your Meats
In order to tell whether a cut of meat is fresh, you need to go by smell and appearance. If a piece of meat is looking grey and smells a little nasty, chances are that it's spoiled. You do NOT want to eat spoiled meat.
You're Pouring Grease Down the Drain
If you pour grease down the drain, you can be contributing to a giant fat deposit in your community's sewer system. Instead of putting any type of fat down the drain, just save it in a heatproof container and throw it out when it cools.