A fictional dialogue that is all-to-often how it actually happens:
Vocation Director: "So James, can you see yourself entering into religious life with us?"
James: "Very likely, but I am waiting for a sign from God."
Vocation Director: "What would that sign look like to you James?"
James: "I don't know, I guess, I think, you know, a sign..."
Vocations Director: "Well that doesn't help. How about if I propose some signs for you?"
James: "Ok, sounds good, go ahead."
Vocation Director: "Has anybody ever told you that you would make a great priest or religious?"
James: "All the time! I can't count the number of people that have told me that exact thing."
Vocation Director: "Have you even dreamed about saying Mass, hearing confessions, visiting the sick, praying with the troubled, or teaching and preaching."
James: "Pretty much all the time these days. Those things are always on my mind."
Vocation Director: "When are you most happy, James."
James: "When I am at Mass or praying or sharing my faith and the teachings of the Church with family or friends. Also, I love reading theology and other good books about the faith and the saints. Those things make me most happy."
Vocation Director: "Can you see yourself getting married and having children someday."
James: "Sometimes; I think that is a good path and I love my family, but it doesn't excite me the way living and sharing my faith in Jesus Christ does."
Vocation Director: "What is the most important thing in your life right now James?"
James: "My faith, without a doubt!"
Vocation Director: So you are still waiting for a sign from God?"
James: "Yes, I just need one little sign, and then I can make a decision about my vocation."
Vocation Director: "Okay, lets try this one more time, James!"