Is the questioner considered mistaken for refusing to shake hands with her husband's relatives and colleagues at work, even though her refusal to shake hands may cause embarrassment or misunderstanding on the part of others?

It is not permissible for a woman to shake hands with a man who is a stranger to her. This is not an act of extremism, but rather adherence to the religion. One must be patient with ill-treatment from the husband's family because of this, and not compromise on matters of Sharia for anyone. Adhering to the Sunnah during times when religion feels alien increases the reward. It is not permissible for a Muslim to compromise on his religion for any reason, and mere embarrassment does not constitute a necessity that permits what is forbidden. The Messenger of Allah, peace and blessings be upon him, said: "Whoever seeks Allah's pleasure by displeasing people, Allah will suffice him against the burden of people. And whoever seeks people's pleasure by displeasing Allah, Allah will entrust him to the people."