It's one of those occasions that can highlight unfairness in a relationship.
Its fine if both parties don't want to put effort into mothers and fathers day.
But you get situations such as
Fathers Day, mother puts effort into reminding children and facilitating them choosing or making cards and gifts. They tell the kids to be quite so daddy can sleep in a little, they prompt and help make Daddy breakfast, or organise brunch or lunch out. Using the opportunity to do some parenting, look kids this is one way show appreciation to someone we love. At no point does he say, inbetween bites of bacon and slurps of beer no love sit down, Your not MY Father! I will wait until the children are old enough to do everything by themselves. Of course they probably never will because they wont have grown up with Fathers day as a thing.
Mothers Day comes, "but you're not my Mother! I'm off to take all these things to my Mother whlist you look after the kids and so have more work to do than usual.
Mothers Day in my house revolves around my husband going to visit his mother, which is fine. We can't go anywhere because its mothers day and he seems to think she will combust if for ONE year she doesn't get to make him tea whilst he hands over some flowers, on a mothers day itself. He would never come to visit my mother because it's Mothers Day. Now this would all be fine if every fucking year he looks so shocked when I don't tag along to see his mother 
Yes, darling you keep saying it's mothers day, it is not mil day. I am going to sit at home and drink wine whilst you take the kids with you,