Some folks just sort of think Holidays are fun for everyone. They are not, and often can exaggerate deep pain to almost unbearable level; especially when a tragedy is connected with it.
With us it was Easter for a long time. My mother-in-law passed suddenly on Good Friday and was buried on the day after Easter. It took several years to climb out of that. Just this blue cloud rolled in about a week before Easter. It is a weird thing how that happens, and you can't seem to plan around it. We kinda stared it in the face and talked it out, more than once, and it has made us stronger, but it was a long haul.