How many people would you have to gather in a room for there to be a 99.9 chance that two people shared the same birthday? It turns out that it is fewer people than most imagine, only 70 people. This is all fine and dandy unless of course you happen to work with these people.

The self-employed are either lucky or unlucky when it comes to birthdays. On the plus side they are lucky because they do not have spend money on cards for themselves, nor do they have to gather in the lunchroom awkwardly singing the Kentuckian Hill sisters “Happy Birthday to you”.

Celebrating birthdays in the office can be divisive, awkward, and an all round waste of time.Credit: iStock

Surprisingly, that song has only been around for 131 years. I wonder what they did before then? The downside for the self-employed, is that they do not get the enjoyment of seeing their colleagues awkwardly eating cake from paper plates while not quite disguising their irritation that the interruption has caused to their day.

The employed are far less fortunate. Especially in large organisations. If you are employed in one of the top 55 traded public companies in Australia, which employ over 2365 people, it is probable that there is a staff birthday on every day of the year. That is about 1.2 million employees who face the prospect of one or more birthdays every day at work.

The trouble is that birthdays are potentially divisive. Not everyone likes to celebrate birthdays. A range of different faith groups and sects including some Christian, Islamic, Orthodox Jewish and Hasidic communities do not celebrate birthdays.

For many people, they are indifferent, embarrassed or even depressed at the prospect of their birthday. For those facing “milestone” birthdays, particularly in later years, the prospect of turning 40, 50, 60, 65 or 67 is not an occasion for celebration.

Birthdays are a time waster, but woe betide anyone who raises that complaint for fear of being thought of as a heartless slave driver.

For employees more advanced in years, marking the occasion each year in public may serve only to reinforce stereotypes associated with older employees, and possibly encourage speculation about the dreaded question. When is she finally going to retire?

Birthdays can be a huge time-waster. Staff are corralled into the lunchroom by the birthday whips. There are always birthday whips. Their work duties appear to extend only to organising a cake, a card and sending repeated reminder emails to all, and then pestering people to sign said card, and shepherding reluctant attendees.