What troubled Yisro that caused him to intervene?
Rashi, Rashbam and Targum Yonasan: He was troubled by the fact that Moshe sat whilst all the people had to stand - a slight on the people's Kavod. 1
Seforno: He was troubled by the fact that Moshe was busy all day dealing with the leaders, who came to him with communal matters, whilst the people with their personal problems had to wait for his attention.
Rashbam and Targum Yonasan: (Not that he expected Moshe to provide them all with chairs - Oznayim la'Torah, but) because he was the sole judge of the entire nation, and appointing judges to assist him would alleviate the problem.,