In that case 23 April (Secretaries' Day) or 15 October (Bosses' Day) probably means nothing either. If Mother's and Father's Days weren't enough, there is now a proliferation of greetings cards for almost any day of the year to show appreciation for those around you - or to induce guilt if you forget.
There are now greeting cards for around 21 special days of the year, encompassing saints' days, and religious festivals as well as the more unusual.
Today is Nurses' Day - so chosen because it is the birthday of Florence Nightingale, the pioneer of modern nursing. While the Royal College of Nursing is putting out surveys to gauge reaction to the idea, Clinton Cards have as many as six different design of cards to mark the occasion.
A spokeswoman for the RCN said: "We've encouraged the Nurses' Day cards and we welcome the fact that it is getting bigger and bigger across the world ... It should be a huge celebration of the work of nurses, a chance to recognise and value them."
John Condon, purchasing director for Clinton Cards, said the company had sold 10,000 of these cards last year and was hoping to shift as many as 15,000 this year - small beer, however, when compared to occasions like Valentine's Day when sales are in the millions. "People think a lot of nurses, they do so much for so little and this is a way of saying thank you," said Mr Condon. "I think it's a combination of families who have got people with nurses in and those who have been in hospital who want to say thank you to those who have looked after them."
Like Nurses' Day, most of the ideas for new cards originate from America - although Age Concern has trademarked Grandparents' Day which falls on 27 September this year. "We did it to raise awareness that grandparents are important members of society," said a spokeswoman for the charity.
"We trademarked it so that we could get donations from the cards sold, although that hasn't worked so well in the last couple of years."
Religious festivals such as the Jewish Hanukkah and Passover, the Muslim Eid-al-Fitr [end of Ramadan] and Eid-al-Addha [to celebrate Haj - a festival that takes place in Mecca] - and the Hindu Diwali [festival of lights] have been taken up by mainstream card companies.
Other recent innovations include patron saints' day cards - for St Andrew, St Patrick, St George and St David. "St George's Day has come on in leaps and bounds," said Mr Condon. "This is the third year and we have had lots of correspondence thanking us for introducing it."
For the consummate crawler, Bosses' Day has been a godsend. Last year saw 1,500 fawning employees buying cards for their employers - although Mr Condon said that the favoured tone appeared to be "mickey taking and joshing" rather than serious.
t Almost half of Britain's casualty nurses have been assaulted at work and almost all of them, 96%, have suffered verbal abuse. The study by ICM for the BBC's Here and Now programme and Nursing Times also showed that one in three of 500 nurses interviewed felt unsafe at work and most believed not enough was being done to protect them.