Apparently there have been issues when US and British forces have worked together before du to the “I thought you were exaggerating” mindset.
The brits have a tendency to downplay really bad situations to the point where, “It’s actually quite chilly” means “We’re in deep shit”. I read somewhere that this caused serious miscommunications several times, because Americans didn’t understand that brits were downplaying things, while brits though the Americans were always exaggerating.