There is nothing wrong with decorating your house, even if Jehovah's Witlesses live there, if you own the house or are paying for the apartment. Hopefully, they will either get stressed out and not be able to function at boasting sessions, or will realize what they had been missing out on and be tempted to do "just a little" (which gets added to) next year.
I know for sure that, if I had witlesses staying with me, they would have to tolerate Christmas decorations (and they get left up all summer). Not only that, but they would have to accept that I have 9 CD's worth of Satanic sermons (which I use in lieu of church), black candles from a Satanic business, a Ouija board, Crisis of Conscience, several other books designed to stimulate free thinking, whatever music including filthy rap and Christmas music I feel like listening to, home-burned YouTube videos of whatever I feel like burning including Christmas, anti-Christian, and whatever adult porn I chance to throw in for good measure, and whatever material things I feel like getting. And they can't do a damn thing about it--throw away my items, I throw away their littera-trash and paraphenalia in return.