What were the nations around Israel like that had kings?
The surrounding nations that had kings were pagan idolaters. Every one of them worshiped false gods, and none had knowledge of the one true God. Israel alone possessed that knowledge. These nations served as the model the elders wanted to imitate when they demanded a king to rule over them like all the other nations.
Les points out that when the elders asked Samuel for a king, they wanted to be like all the other nations around them; everyone had their king. But God had made Israel different. In His covenant with Abraham and Moses, Israel was to be a set-apart, sanctified people, not like the rest of the nations. Les says he imagines Israel knew those surrounding kings were pagan idolaters, and no one but Israel had knowledge of the one true God. Samuel was heartbroken, but Jehovah told him to let the people have their way, because they had rejected God, not Samuel.