One of the ways that I check to see if a call to the priesthood is authentic (not the only way, but one of the ways, mind you) is that the young man sitting across the desk in my office is flabergasted that he made the call is sitting talking to a Vocation Director. Often, this astonishment is accompanied with a line: "I had my whole life planned out, but I could shake this idea of the priesthood."
It is an amazing and profound realization that one might be called to the priesthood. With St. Peter, comes the protest: "Leave me, Lord, for I am a sinful man."
If the call to the priesthood is amazing enough, how about the call to be bishop. This one is literally a call, usually from the Apostolic Nuncio's office. I heard one bishop tell: "I nearly dropped the phone! I was stunned, and the only thing I could get out was, 'Can I call you back in an hour?'" (He did, by the way, with an affirmative.)
By now, you've likely heard that St. Louis Archbishop Raymond Burke has been called to Rome to head the Apostolic Signatura, the Church's Supreme Court, as it were.
What could one do to ever prepare to answer that phone call? Who made the call, anyways? BXVI? Sodano?
I think I would pass out!
Send prayers for your bishops and priests, we need them!