This always feels to me like the end of a movie. When you're in a movie theater, it's dark and everything is focused on the screen, and then they suddenly turn the lights on and throw you out into the world. No one is ready for that transition, and it's always a shock, and you always feel a little dazed -- you've been in an alternate reality for hours, and suddenly, you're back in the real world.
The disciples must have felt like that. There's no time to comprehend it all -- suddenly, Jesus is gone, and the angels don't give them time to linger. They wonder why the disciples are staring into heaven, and then they remind them that they are sent into the world. Their job isn't to stare uselessly into the clouds, but rather to go forth into the real world, into the messy and often-jarring world, and proclaim the Gospel good news to all people.
May we not spend all our time staring into heaven. There's a time and a place for us worship and adore God, and then we go out into the world to preach the Good News. It can be a shock, a radical departure from our time of worship, but that's who we are called to be -- a people in the world, serving the world, loving the world.