During dinner Harry watched Professor McGonagall pointedly turning her back to Snape who had his seat on her right side as he was the deputy headmaster. The headmistress consistently spoke to Professor Flitwick at her other side and did not exchange a word with the Potions Master. Meanwhile, Hermione hardly got any food down as she was leaning in on Harry and Ron, explaining her discoveries at the library. 

”The Enchantment can only be brought on by a wizard or a witch who has no personal interest in Christmas, someone who does not want anything for himself,” she said. Harry raised his eyebrows.

”No personal gain? That sounds very unslytherinish,” he commented. 

”The exact wording was ”someone who expects nothing from Christmas”. That’s why it’s so difficult to find the right person, you see. Most of us expect something - if not presents, maybe good food or company or family traditions that you want to repeat. Those things go deep in you since your childhood. It’s extremely rare to find someone who expects nothing,” explained Hermione.

”Yeah… well, if you loathe Christmas, as Snape clearly does, I guess you don’t expect anything, but then you don’t have a reason to do such a spell,” answered Ron.

”It must be done solely for the benefit of others, as a gift to your fellow-beings,” Hermione explained further. 

”And only Dumbledore could make Snape participate in such a scheme and now that he’s gone, Snape refuses to go along with it. How selfish of him,” Harry reflected slowly and shot a pondering glance at the teachers' table. Strangely, Snape was staring back at him at the same moment and after holding the teacher’s gaze for a short while, struggling not to show his disapprobation overtly, Harry turned his eyes away.