Hadith: O people, you cause aversion to others. Whoever leads people in prayer should make it brief, for among them are the sick, the weak, and those with needs to be fulfilled

عن أبي مسعود الأنصاري رضي الله عنه قال: قال رجل يا رسول الله، لا أكاد أدرك الصلاة مما يطول بنا فلان، فما رأيت النبي صلى الله عليه وسلم في موعظة أشد غضبا من يومئذ، فقال: «أيها الناس، إنكم منفرون، فمن صلى بالناس فليخفف، فإن فيهم المريض، والضعيف، وذا الحاجة».
[صحيح] - [رواه البخاري]

Abu Mas‘ūd al-Ansāri (may Allah be pleased with him) reported: A man said: "O Messenger of Allah, I would almost fail to attend the prayer because so-and-so prolongs it when he leads us." I never saw the Prophet (may Allah's peace and blessings be upon him) more angry in giving admonition than he was on that day. He said: "O people, you cause aversion to others. Whoever leads people in prayer should make it brief, for among them are the sick, the weak, and those with needs to be fulfilled."
Sahih/Authentic. - [Al-Bukhari]

Explanation

A man complained to the Prophet (may Allah's peace and blessings be upon him) that he would sometimes join the congregational prayer late because the Imām prolonged it. Thereupon, the Prophet (may Allah's peace and blessings be upon him) got extremely angry and addressed the people, admonishing and warning them that they should not make others averse to worship. He commanded that the Imām should offer the prayer in a brief manner to make it easy and pleasant for the worshipers, among whom there may be some who cannot endure a long prayer because they are weak, sick, or preoccupied with certain needs that are to be fulfilled. If a person prays alone, however, he can make his prayer as long as he wishes, for he causes no harm to anyone by doing so.