Holidays and New Years are meant for family togetherness, and often this means dinner with your in-laws. But, the holidays can be a stressful time, and if your mother-in-law oversteps her boundaries and starts acting like she's the mother, it's likely you'll both end up upset. Although cliches about in-law tension are often true, the best way to deal with these situations is with perspective and sympathy. Most mothers-in-law are simply trying to navigate the maze of their relationship with their son or daughter without any help from their own culture or family..