The stiff upper-lipped stereotype image of the English is not borne out by a new study of personality traits in 49 different cultures.
Popular national stereotypes bore little resemblance to real people
Nearly 4,000 people were asked to describe "typical" members of their own country and these were compared with assessments of real-life individuals.
Misconceptions can be perpetuated through education, hearsay, the media and jokes, US researchers said.
The National Institute on Aging study is published in journal Science.
"People should understand that we are all prone to these kinds of preconceptions and likely to believe that they are justified by our experience, when in fact they are often unfounded stereotypes," said Dr Robert McCrae.
"National stereotypes can provide some information about a culture, but they do not describe people.
"In fact, unfavourable stereotypes of national or ethnic groups are potentially very dangerous, forming the bases for prejudice, discrimination, persecution, or even genocide."
The study found there was a widely held belief that most Germans were industrious, Italians passionate and English phlegmatic - but found there was little truth in those views.
Americans and Canadians had almost identical scores on measures of assertiveness.
But researchers found Americans rated themselves assertive while Canadians believed themselves to be submissive.
Indians turned out to be more conventional than anyone else surveyed but saw themselves as unconventional.
The NIA researchers now plan to look at age stereotypes around the world.
Previous studies by the institute found stereotypes depicting old people contribute to age discrimination.