Identify countries, which lack at least one extreme point. In other words, the northernmost, easternmost etc. point does not exist, because there is a straight line of latitude/longitude, thus there might be infinite extreme points of this particular cardinal direction.
Using a map is recommended.
Indonesia and Kuwait do not count. Indonesia's eastern border looks like it, but the southern point of the line is much more eastern than the northern. Similar situation with Kuwait and its southernmost point. Sudan and Tanzania are also honorable mentions with their northernmost points.