Many Muslim women who wear the hijab will tell you they have experienced that awkward moment. A man will reach out his hand to greet her in a professional setting, and she will have to make an impulsive decision on whether she should reciprocate the gesture.
For Muslims living in the U.S., greeting the opposite sex by shaking hands could create a dilemma. Many Muslims believe that shaking hands with members of the opposite sex is not permissible, unless the two individuals are blood-related or married.
While this Islamic teaching has been enforced in the religion for hundreds of years, in modern day society, some Muslims will make exceptions to adapt to their westernized settings.