Angel Visitations

I was reading the first chapter of Luke in a sample of The ESV Study Bible that I picked up at Mardel this weekend, and I noticed something that I hadn't noticed before. Zechariah and Mary both had visitations from an angel with very similar circumstances surrounding it, but their reactions and the result were quite different:

Both were visited by the angel Gabriel.
Both were "troubled" by the visitation, but while Zecharaiah was fearful, Mary sought understanding (although it could be argued that Mary was afraid also.)
Gabriel told them not to be afraid.
Gabriel told them they would "bear a son, and you shall call his name..."
Those sons would "be great" and do amazing things.
Zechariah responded by asking for a sign (which he then received, to his chagrin). On the other hand, Mary asked for details of what would happen, but then she accepted the Lord's assignment without resistance.

Why was a priest surprised by or afraid of an angel appearing in the temple where the Presence of God was expected to be, when a little girl in her house seemed to take the appearance of the same angel almost as a matter of course? Maybe Zechariah was thinking about how priests could face death for entering God's presence unworthily (although he was not actually in the "Holy Place inside the veil" but on the other side of the veil where incense was burned) and that sometimes angels were sent to kill people. Why was the priest struck mute (and probably deaf as well) for asking for a sign? Maybe it's because he doubted the clear word of the Lord ("How shall I know this?" Because GOD said it, fool! Don't you see the angel??) Mary did not doubt, but did ask for clarification. Even then, she did not demand an answer, although she did receive one.

People in ministry are sometimes held to higher standards by God than the rank and file, and that may have been part of it, but I think Zechariah reacted to the word of the Lord in fear and doubt, while Mary reacted in submission. I think that's why Zechariah spent the next nine months in silence, while Mary got to spend it glorifying God!