I found the appearance of Gabriel and other angels, and how people reacted to angels to be very interesting.  First Gabriel appears to Zechariah, who would be the father of John the Baptist. When Zechariah saw Gabriel, he was very afraid. (Luke 1:12) While Zechariah was in the temple the priests entered to burn incense and they found him there and he could not speak which was because he had doubted the angel’s words.  The angel had revealed to him that his son would be no ordinary child but would be a great prophet who would, “Go before the face of the Lord to prepare his way” (Luke 1:76).  When he finished his time in the temple, he went home.  Soon after his wife Elizabeth who was previously barren became pregnant.