I know witness couples who have had very large, very expensive anniversary parties complete with giant photos of the couple, speeches about the couples wonderfulness, dancing, gifts, the whole shebang. Mostly they are older couples the husband a much adored elder, the wife would win the stepford wife of the year award, children (if any) are at bethel or pioneering.... you know the type.
But birthdays? Noooo that's glorifying the individual, whereas anniversaries glorify Team Jehovah!