In "the £1,000,000 bank-note," why did mark twain most likely create the character henry adams as an american living in england?

Unlike other realist writers of the time who enjoyed writing about Europe and thought that America wasn't as developed, Mark Twain created his American characters in Europe in such a manner to mock everything and everyone, showing Americans often as people who don't know how to behave, while at the same time showing Europeans as overrated, and not generally as advanced as they would have you think.