Harry Wallop described receiving a free Pret coffee as winning the lottery. He returned to the office “like a conquering hero”. The drink was worth a few pounds. The uncertainty supplied the ridiculous amount of theatre.

A predictable tenth coffee becomes part of the deal long before it arrives. Customers count towards it. The eventual free cup settles a debt. An unexpected cup can feel personal because no card has matured and a member of staff appears to have noticed the person standing there.

That appearance is doing delicate work. Replace the server with an automated wheel and the surprise starts resembling a game mechanic. Increase the frequency, hide the odds and encourage repeated purchases because the next one might win, and the loyalty scheme has wandered towards gambling with a milk option.

Discretion creates a different problem. Regulars notice who receives generosity. Staff have friends, favourites and unconscious patterns. A delightful exception for one customer can look like exclusion to the next six people in the queue. In a workplace, unexplained surprise rewards become an anxiety-production system for everyone overlooked.

The boring controls are therefore part of the idea: a modest allowance, no rewards for friends, checks on distribution and a basic service good enough to survive a day with no freebies. Too much published precision turns the gift back into an entitlement. Too little oversight lets charm become favouritism.

There is no magical “add randomness” setting. Context decides whether uncertainty feels generous, manipulative or unfair. The same irregular reward can produce a story told fondly at the office or a customer quietly counting how often somebody else gets picked.

Tomorrow’s queue forms. The first five people pay. The sixth is handed a coffee and smiles. Two places back, someone notices.

Behavioural principles

Behavioural ideas at play in this post

Short, plain-English explanations of the principles behind this post, with links to related books and examples in the archive.