Have you ever found yourself clammy-handed as you awkwardly leave a restaurant abroad, unsure of whether you’ve tipped an insultingly low sum or a foolishly high amount? Or realised to your horror that the bellboy at an American hotel will expect a crisp dollar bill, and you have nothing smaller than the $50 bills you exchanged at the airport?

Whether you’re stepping into an American hotel room after an 11-hour flight, or leaving a restaurant after a romantic night out, the practice of tipping regularly introduces a sour, stressful note into what should be a carefree moment.

Tipping etiquette might seem like a tiny thing to get in a tizz about, but psychologists now recognise “tipping anxiety” as an increasingly common form of social anxiety. It throws up all sorts of questions that you really don’t want to mull over as you contentedly suck on a wafer-thin mint.

Will the staff think we didn’t enjoy our meal if we leave anything less effusive than 20 per cent of the bill? Who am I to decide if the server should be punished or rewarded for doing their job? Perhaps she’s just having a bad day! Will my companions think I’m a mug or a miser according to how much I tip? Is the server reliant on generous tips; oh God, what a sad thought? Who has more power in the relationship between server and customer, and would I rather be the powermonger or the power-free party in this whole sorry exchange? How would someone slick and serene handle this situation?