Sometimes a war driven culture is not always beneficial to creating a functional society. The Agoge caused several problems for Spartans as any man who could not complete it would be denied Spartan citizenship, reducing the population of the state. Far north of Greece, in Scandinavia, their were many places in which war and fighting was a fact of every day life.
These people had to balance short farming seasons with raiding seasons, and while it is unfair to say that ever norseman was a raider, there are many places in which it thrived. The Icelandic phrase "Fara  vkingr" meant to go on an armed expedition based upon plunder and looting, These raiders were successfull in sieging even walled baileys and towns by marching in great shield walls and using <link="proto:portable ram">rams</link> to bust down gates.