As Washington, I once reduced Hiawatha to a single tundra city. Eventually Askia asked to open borders because he wanted to wipe out Hiawatha. I let him and he gets 8 units settled up right next to his last city and.. nothing happens. He has mud cavalry and cannons and does nothing. Askia does nothing to try and take that last city. Is it because Askia was in my borders even though I let him? What, was he really waiting on reinforcements to take a 5-tile tundra city that had no units and would've wiped Hiawatha off the face of the earth?
Then it just gets frustrating to see Hiawatha's units die to city bombardment because they're standing in range of the bombardment but are still sitting there waiting for.. something? Next time Askia asked for open borders I just told him no. He didn't deserve to take out Hiawatha if he was going to derp like that.
And it's really frustrating because 20 turns prior he had no trouble going to war with Greece with me and snagging a few of Alex's his last cities that I actually wanted to own.