My daughter hates Christmas and that always ruins it a bit for me. When she was younger she hated getting presents she didn't really want, hated being watched whilst she opened them, hated the fact that her Dad wasn't around when her step-siblings had theirs, hated the music, hated that her Birthday was a week before, created loudly and temperamentally over everything. Once she grew up she would be looking for trouble and estrange me over the festive period. It used to be horrible because I would be crying on the inside but trying to put on a happy occasion for the younger ones.
She got a little better after her children were born but can still find it difficult. On the upside, I have learned that it isn't something personal against me, she just can't handle her emotions and has Borderline Personality Disorder. For years, I was damned if I invited her because I know she hates Christmas and obviously hated her if I didn't invite her! We now have an agreement that she is automatically invited but I will understand if she can't face it. It is starting to work much better so maybe she won't always feel Bah Humbug but by the time she gets there, I'll probably be feeling it as it is such a hassle with all the expense, the wrapping, putting the decorations up, etc, etc!