the.com/wet blanket

The one person who treats fun like a fire that needs extinguishing.

means Someone who dampens other people's enthusiasm or enjoyment, often by being gloomy, critical, or overly cautious at a moment meant for fun.

from This one is refreshingly literal: a real wet blanket was the go-to tool for smothering flames before fire extinguishers existed — tossed over a campfire or a stray spark, it kills the blaze fast and effectively. By the 1800s, English speakers had stretched that image into a metaphor for a person who snuffs out the mood of a room the same way, wet wool on dry joy.

literal origin
Sailors smothered flames with actual wet blankets
first recorded use
Early 1800s, meaning a damper on enthusiasm
social function
Kills momentum faster than bad WiFi
irony
Often correct, rarely forgiven for it
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