Christmas is the time of the year when families gather to celebrate and spend time together. At the same time, all families have members that attend these gatherings despite not being wanted there for various reasons.
In this story, the unwanted family member ended up being this woman whose sister vented online about not wanting her over during Christmas. Then, when netizens asked the OP to name what was actually so bad about her sibling, she started rambling about a difficult personality, but it didn’t convince all online folks, which turned the post’s theme from a Christmas party to a rivalry between sisters.
More info: Mumsnet