It is narrated from Sayyiduna Abu Mas'ud (may Allah be pleased with him) that a man said: O Messenger of Allah, I pray behind so-and-so, and he makes the prayer long, so sometimes I hold back. At this the Messenger of Allah (peace and blessings be upon him) became so angry that I had never seen him (peace and blessings be upon him) so angry in any admonition. Then he said: "Among you are some who drive people away. Whoever leads the people in prayer should keep the prayer short, for among them are the weak, the old and the one with a need."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14628