On What Sort Of Greeting

Luke 1:26-30
"In the sixth month the angel Gabriel was sent from God to a city of Galilee named Nazareth, to a virgin betrothed to a man whose name was Joseph, of the house of David. And the virgin's name was Mary. And he came to her and said, 'Greetings, O favored one, the Lord is with you!' But she was greatly troubled at the saying, and tried to discern what sort of greeting this might be. And the angel said to her, 'Do not be afraid, Mary, for you have found favor with God.'"

This is from the Christmas Story. I think its tremendous that Mary was staring at an Angel, and she had to sit there and try to figure out what the junk was going on. Because seriously, how often to angles show up and announce to you that you're pregnant? It's happened once.

I think we spend a lot of time trying to discern "what sort of greeting" God's giving us. Every time I face a major life decision, I spend hours "trying to discern". I think it might be endemic to evangelical christianity. We teach ourselves that we need to listen to God. You tell someone, "i'm thinking about studying abroad", and all they say back to you is, "Pray about it. Listen to God."
That's more or less a useless answer, obviously I asked for your advice because I wanted your advice, not a canned response that's just going to paralyze me with inaction.
How do we get over the trying to discern part? Mary didn't have to understand what was going on. For all we know, she didn't know what was happening until after Jesus rose from the dead. Somewhere along the way, like His disciples, she must have thrown in the towel on trying to discern and just let Jesus reveal himself to her.
How do we do that?
How do we let go of trying to understand the universe? And how do we let go of always trying to figure out what sort of greeting this is?