Crossing Your LegsHow bad is it? Don’t stress over this one. Forget the old wives tale about crossed legs causing varicose veins—whether you get those is based solely on heredity factors. And while crossing your legs can temporarily elevate blood pressure (which is why physicians often ask patients to keep their feet flat during checks) there are no long-term heart-health effects from sitting with your legs crossed. Instead of worrying about how you’re sitting, you should be worried about how much you’re sitting, says Deirdre Mattina, MD, member of the American College of Cardiology. Numerous studies have shown that prolonged sitting is associated with an increased risk of developing cancer and diabetes, among other health issues. “Basically, the more hours you sit, the quicker you die,” says Mattina.The fix: It’s pretty much impossible to avoid sitting altogether, so Mattina suggests taking frequent walking breaks. If you’re at the office, stroll over to someone’s desk to chat instead of sending an email or simply set yourself a little reminder to get up and move every 30 minutes or so. MORE: The Antidote For Sitting All Day Biting Your FingernailsHow bad is it? It’s not horrible, but it’s also not harmless. In addition to giving you funky-looking fingernails, nail biting can damage future nail growth. “Chronic nail biting can change the shape of the nail permanently so that they grow shorter and wider, making nails look stubby,” says Dana Stern, MD, professor of dermatology at Mount Sinai Medical Center in New York. That’s because frequent nail-biters are constantly damaging their nail matrix, the delicate, soft-tissue structure that produces the hard nail. Biting can also lead to nail discoloration and infections from outside bacteria and yeast from the mouth.The fix: Since nail biting is often linked to anxiety, finding out why you have the urge to nibble is the first step (working with a psychologist or psychiatrist may help). Then, Stern suggests dropping some cash on regular manicures. “If you keep them polished, you’re investing in them and it makes you pause before you bite,” says Stern. The only downside: chipped or peeling polish, which can trigger the urge to nibble or pick. MORE: 7 Things Your Nails Say About You Cracking Your KnucklesHow bad is it?arthritisThe fix: Not a big deal—unless you do it 24/7 The satisfying (or, to others, really gross) sound of a knuckle cracking is actually joint fluid moving around in your digits, meaning the popping sound you hear isn’t doing any major damage, unless you’re doing it incessantly. “If you do it constantly, you’ll wear out the ligaments in your joints,” says Leon Benson, MD, orthopedic specialist and spokesperson for the American Academy of Orthopedic Surgeons. Stretch out those ligaments too much and you could seriously impair their functioning, which could lead to . Chronic knuckle cracking is often linked to anxiety, so any type of treatment has to first begin with psychiatric help, says Benson. But for less intense or just occasional crackers, simply being more mindful of when you have the urge to crack and trying to stop yourself may be enough. Texting (Or Facebooking Or Instagram Stalking) In BedHow bad is it? Proceedings of the National Academy of SciencesThe fix: You need to stop doing this—today Smartphones are the grown-up equivalent of a security blanket, but taking it to bed with you isn’t a good idea for your sleep schedule. “Cell phones emit a blue-green wavelength of light that’s stimulating to us,” says Diane Augelli, MD, assistant professor at the Weill Cornell Center for Sleep Medicine. That extra stimulation suppresses melatonin (a hormone your body produces to promote sleepiness), making it harder to fall asleep and stay asleep. What’s more: chronic melatonin suppression could lead to an increased risk of breast, colorectal, and prostate cancers, according to a study published in the . “Ideally, you would just set your alarm before bed then not look at your phone again until the morning,” says Augelli. Many experts go as far as to suggest turning off all electronics at least an hour before bed. Either way, it all comes down to willpower: “If you’re worried about your sleep and your cell phone is impacting your sleep, you just have to make the choice to stay away from your phone,” says Augelli. MORE: 20 Ways To Sleep Better Every Night Skipping BreakfastHow bad is it? It’s not great. On harried mornings, breakfast often feels like a luxury you just can’t afford. But failing to break that overnight fast deprives your body of the fuel it needs to rev your metabolism and give you enough energy to start the day, says Alissa Rumsey, RD, spokesperson for the Academy of Nutrition and Dietetics. Denying your body of that morning meal can also make you hungrier and more likely to overeat later in the day, and may even affect your concentration and memory. And if you skip breakfast on the regular, you could permanently slow down your metabolism, putting you at risk for issues like weight gain and diabetes.The fix: Use your weekends to prepare for the week. “Hard-boil a bunch of eggs, which are easy to grab in the morning, or stock up on containers of Greek yogurt with some nuts and fruit,” says Rumsey. Smoothies are another easy solution—tossing dry ingredients into a blender the night before and adding liquid in the morning to blend cuts morning prep time in half (these 5 smoothie pack ideas will get you started). Still short on time? Stash some breakfast essentials at work—you’ll still reap the same benefits of an immediate breakfast if you eat within an hour of waking. MORE: 9 Almost-Instant Breakfasts That Practically Make Themselves Clearing Your ThroatHow bad is it? Pretty bad We usually clear our throats when we feel like something is stuck in it—totally normal during cold and flu season with the extra mucous created by sniffles and sneezes. But the problem with throat clearing is its habitual nature: “Throat clearing can become a vicious cycle; the more you do it, the more you want to do it,” says Dale Tylor, MD, an otolaryngologist at the Washington Township Medical Foundation in Fremond, CA. And anytime you clear your throat, you’re slamming your vocal cords together more forcefully than usual. “If you do that enough, you could get calluses or nodules on your vocal cords, which can significantly worsen your voice, making you very hoarse,” says Tylor. Habitual throat-clearers could even develop a vocal cord hemorrhage, bleeding underneath the lining of the vocal cords, which requires speech therapy or surgery to heal.The fix: Each time you feel the urge to “ahem,” take a sip of carbonated water, suggests Tylor. A a 2007 study that found 63% of throat-clearers noticed a reduction in their urges after sipping some ice-cold seltzer. MORE: 5 Things Your Blood Type Says About Your Health