I think to many of us read too much into the trivia of life; like Mother's Day/Mothering Sunday, birthdays and all kinds of anniversaries and seem to see any dereliction from the required norms as rejection.
What matters is what your relationship is with the family member involved. DS has the memory like a sieve. I may get a MD card or I may not, I may get an apologetic phone call. DH rarely remembers to buy me a card on any special day but we always have a nice meal out. We have been married nearly 50 years and are happy together and it is the same with DS. We have a close and happy relationship with him, DDiL and DGC even though we live 200 miles away.
Yes, a card and flowers are nice, but no necessity, knowing that I am part of a family where we all care for each other is what is important.
Soops kitchen, a place of reflection, refuge and at times revelry.
. I always looked forward to receiving cards from our boys on Mothers Day, especially when they were little and made them themselves.