for me, it's probably seeing 5,6, or 7 star heirs mature that aren't first in line to take over the throne when the King dies. that, or being pleasantly surprised by how fun certain factions can be that i've never used before. i've still never played as any of the Muslim, Pagan, or Scandinavian factions and have never really finished any of the campaigns that i've started with Orthodox factions, so hopefully there's a few more pleasant surprises down the road.
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