Are you having a bad underwear day? According to a new study, it’s not just bad hair that can affect a woman’s mood. An ill-fitting or ugly pair of panties also has the power to ruin a woman’s day. ShopSmart magazine conducted a telephone survey of 1,008 women 18 and older about intimate apparel and found that 47 percent feel sexier and more confident wearing a nice or special pair of undies. "The first thing we put on in the morning does make a difference in our day," said Lisa Freeman, editor-in-chief of ShopSmart. Here are some other interesting finds: The average woman owns 21 pairs of underwear. Overall, 46 percent say briefs are the style they wear the most often, though women age 18-34 are more likely to wear the bikini style. And 1 in 10 women admit that they will venture out of the house sans panties from time to time. What do you think, ladies? Have you ever had a “bad underwear day?” What style of panties do you prefer? What kind of underwear makes you feel the most special? How many pairs do you own? Ever left the house commando? Men, do you experience bad underwear days too? What kind of panties do you like your women to wear?