My wife's mother passed away a couple of months ago, so this Christmas was always going to be difficult.
My niece - who is a high-maintenance princess with an "it's all about me" aura and a somewhat-justifiable dislike of her brother - arrived for Christmas Day lunch yesterday, sat in the car until I (with my wife and son) arrived before getting out and joining the rest of the gathering, then walked inside to give her greetings then promptly sat on the couch with her fiancé and didn't interact with anyone unless requested. We gave our presents, and she gave out hers - which included a deed/certificate showing that she'd gone to the effort of getting a star named after my now-dead mother-in-law. A fantastic gift, sure, but one that was always going to make the day far more difficult than it already was, given it just served to open up the still-fresh wounds of the MiL's loss. Then my niece said it was all too emotional, went outside, and decided she couldn't stay any longer and left - before lunch was served.
Yeah...not impressed.