They’re conflicts waiting to happen because of unreconciled differences.
For example, when the British arbitrarily fashioned states (like Iraq) in the Middle East, they drew boundaries that didn’t take ethnic or tribal allegiances into consideration. Even though those states were, theoretically, unified entities, in fact they were only held together by force of autocratic governance. All of the religious and tribal tensions among the various groups created fault lines, weaknesses in the social fabric that would cause the rupture of those tenuous aggregations under stress.