You crush them and bring them under your control - and suddenly you find revolutions popping up everywhere. You start again and this time you find a weak neighbor with no allies. You start over as a bigger country and attack a smaller neighbor - and suddenly you're in a war against several large countries at once.
You have a country and three thousand infantrymen - what can you do? You decide to attack your neighbor - and they cut you down like reeds.
Steep learning curve When you start out, it can be overwhelming.