Is it possible that the image of vikings as bloodthirsty raiders may be incorrect because of simple grammar and cultural norms.
I mean, there's no Danish word for 'please'. The courtesy of the word is inherent in the phrasing of the statement or question.
Maybe the vikings were pacifists driven to starvation fueled violence by uptight, manner obsessed elite, who wouldn't trade with them because they just wouldn't say 'please'.