Did you know...

What about guerrilla wars? Kill one leader and a new one will appear tomorrow.. in a different part of your country.. and totally unexpectedly and, you could say, "randomly". And the strongest features about guerrillas, i think, are 1) that they're "invisible" (and you cannot fight what you cannot see) and 2) that the destruction they cause is worth more than their budget (which makes them extremely cost-effective).
 
But at least you don't live in shit and wait for days, hoping the shells don't land on your unlucky head. That's already mind-breaking to the soldiers. And after the wait, what do you do? You charge to your death!!!