A red flag along a path winding away in the distance

The power of wrong

When might we opt to refrain from doing something that would serve us well?

Koen Smets
6 min readOct 20, 2023


A few weeks ago, the light bulb in our oven popped. It is one of those insignificant items whose utility you don’t fully appreciate until they cease functioning. Not only does it actually help you track the duck-roasting or cake-baking progress without requiring a torch, it is also a handy reminder that you still need to turn the oven off when that process is complete. The bulb itself is one of a kind, and hence not quite a regular purchase. How much would it cost? I had no idea, really. How would I establish what was a reasonable price? I could see a mini case study develop right there!

Thankfully, we had kept the packaging of the now defective bulb, and it turned out to come from the local DIY store, almost next to the supermarket where I do my weekly shop. A quick search online revealed that they had the bulb in stock, and that it cost a nice round £5.00. Perhaps a bit on the expensive side, but then again, it is a low-volume product in a market where incandescent lamps are rapidly disappearing, so a relatively high price is not unexpected. Besides, as I am a rational person, I worked out that the cost over, say, four years (the last time I changed it was definitely before the pandemic), would be of the order of 10p per month, not the kind of expense that would expose me to bankruptcy.

If I had stopped my research there and then, we would long have had light in the (oven) darkness again. But I didn’t — I was too curious.

Within ten minutes, I had found two alternative sources: an online seller offering the same type of bulb for just £1.02, and a store at the other side of the town selling a pack of two bulbs for £2. Suddenly, the £5.00 option had lost much of its shine. What to do?

A cutting from a web page for an oven bulb
Much ado about a £5 oven bulb…

My rational self tried to assert its authority, arguing smugly that it is not the headline price that should matter, but the overall cost (including non-financial cost). The £3.60 shipping cost of the online store would bring the total cost so close to my starting point that it hardly made a difference. And, unless I…



Koen Smets

Accidental behavioural economist in search of wisdom. Uses insights from (behavioural) economics in organization development. On Twitter as @koenfucius