 The coffee maker could be making you sick. One study found that 50% of coffee machines have either mold, yeast, or both, and have more germs than a bathroom faucet handle. If your brew tastes weak, bitter, is taking long to make, and isn't as hot, chances are, your coffee maker is gross. To clean it, add a mixture of water and vinegar, and run it through a cycle a few times. And if you're worried about the vinegar flavor, just run it a few extra times with just water, and you'll be good as new.