I always thank both of my parents every day. It does not require a day to do this.
It's nicer to randomly buy flowers, chocolates etc. Same goes for Father's Day with drink, socks, sweets/chocolate.
I have noticed restaurants for MD are doing similar things to Valentine's Day - limited menu and more expensive than normal.
Some people go really OTT with MD. If I buy anything, even a card, I get told off.