I know Paul has caveated advice before in a Startup School talk ('advice = over-generalizations + limited life experience...', I think..). But this seems like such useful advice at all timelines (in work and personal life):

I keep looking for meaning, but all I've found so far is that in order to be at peace with the present, we must be at peace with the past, because the present is a product of the past.

One of those things that's so obvious that it's easy to overlook its importance.