An empty vessel

A lot of times in my prayer, I would ask God to use me. The question is, how much space in my life which I left God to fill?

Lets see... I'm not exactly an empty vessel as I would love to be. I have my own dream, goal, plans to fulfilled. I saw myself in the future as a business analyst who work in a challenging environment. I saw myself serving God from behind the curtain in the church, at my workplace etc.

What if God tells me now, "Leave your job and be a missionaire" Would I be able to say 'YES' undoubtly?

Do we really meant it when we say "God, use me"?