The life of Moses is so large and significant that it's hard to imagine that we have anything in common with him—until he opens his mouth. As soon as he starts to talk he sounds just like us. When he starts offering excuses, he's not saying anything that we haven't used as reasons for not surrendering our lives to God.
I identify with his reluctance. It took me a long time to feel comfortable with my calling as a pastor. I had to be more vulnerable, accessible and responsible than I'd been as an academic, and I wasn't sure I was up to it. This is what makes Moses' encounter with God important—we tend to counter everything God says to us with a quick excuse. When God called Moses, he responded with at least five excuses, all of which believers have stubbornly used throughout the centuries.