The British enjoy a good insult. It’s one of our favourite pastimes, along with complaining about the weather and slagging off the French.
However, we do believe that a truly good insult should also require some thought, and if it is directed at a foreign person, they shouldn’t understand it at all in an ideal world. So when we want to tell people that they are stupid, we do it in a subtle way that mostly goes unnoticed. But we know we have insulted you! It gives us enormous pleasure and a warm fuzzy feeling inside.