First on the list: Nail-biting. When you chew, bacteria under your nails can enter your mouth.
"The biggest problem is infection," said Dr. Sharon Bergquist, Assistant Professor of Medicine at the Emory University School of Medicine.
Second on the list: Wearing contacts too long. As many as 67 percent of people do it, but not changing your lenses can damage your cornea.
"You can also change the shape of your cornea, and that will start distorting your vision," Dr. Bergquist said.
Third on the list: Rubbing your eyes. Doing it too much can thin out the cornea.
Loud music is a vice enjoyed by many, but it can also be dangerous. Twenty-percent of rock musicians have permanent hearing loss, according to studies.
Wearing high heels all the time can cause bunions, hammer toe, varicose veins, and more.
"The inner part of your knee gets a little more wear and tear, and you can get premature arthritis in your knee," Dr. Bergquist said.
Another vice to avoid: Eating too fast. It takes the brain about 20 minutes to recognize the stomach is full, so it's easy to overeat. Bad habit number 7: Skimping on sleep. Getting less than six hours a night can double the risk of heart attack and stroke.
And the final vice to avoid, and maybe the most dangerous: Constant sitting. Women who sit more than six hours a day have a 37 percent higher death rate than those who sit less than three.
Whatever your weakness, remember that moderation is key.
"Any vice can be dangerous if you overdo it," Dr. Bergquist said.
She also shared some good news. You can make up for past mistakes. If you give up smoking, within ten years your risk of death from lung cancer is almost equal to that of a non-smoker. If you baked in the sun as a teen, stopping now can reduce your risk of cancer. You can also give your skin a daily boost with a cup of green tea. A recent study found women who drank it every day for 12 weeks had greater protection from UV rays.