No-one knows.  A few countries can point to specific events that turn their history on its head and shaped their destiny.  For example, the Japanese can make a direct link between the arrival of Perry, the rulers seeing that if they didn't adapt damn fast they would be colonised and the Meiji era.

Most of the rest of us live in countries where cultures have evolved over centuries and are still changing.  The US, Ireland and the UK have a regard for personal freedom, taxation based on democratic consent and property rights that was clearly visible in the 1640s during the English civil war.  100 years before, none of those things mattered.  

And our shared political culture hasn't really had a major change since then.