question #1 Sahih al-Bukhari 530, Book 9, Hadith 9 : What concerns might arise when religious practices are not performed as they were during the Prophet’s lifetime?

Narrated Az-Zuhri that he visited Anas bin Malik at Damascus and found
him weeping and asked him why he was weeping. He replied, “I do not
know anything which I used to know during the life-time of Allah’s
Apostle except this prayer which is being lost (not offered as it
should be).”