question #2 Sahih al-Bukhari 212, Book 4, Hadith 78 : Why is it important to be fully alert and conscious while performing prayers?

Allah’s Messenger (ﷺ) said, “If anyone of you feels drowsy while praying he should go to bed (sleep) till his
slumber is over because in praying while drowsy one does not know whether one is asking for
forgiveness or for a bad thing for oneself.”