When God told Moses to speak to Pharaoh (in Exodus 3 and 4),
1. Who Am I?
2. Who are You?
3. They won't believe me.
4. I'm not a good speaker.
5. I don't want to do it.
God didn't assuage Moses' ego or build up his self-esteem. He didn't talk about Moses at all. He talked about Himself and His ability to do what Moses could not.
It didn't matter who Moses was. It mattered who God was.
God explained He wasn't a little "g" god like those of Egypt, but the Great I Am. He promised to prove Himself to the Egyptian leaders and give Moses words to speak.
I imagine when Moses got to his fourth excuse and said, "I'm not a good speaker," God was thinking, "No, you're not a good listener. I've been trying to tell you that it's not about you. It's about Me."
Most of us can identify with Moses' attitudes. But it's clear that whenever God asks us to do something, all our excuses are irrelevant.