Why did Paul think his fleshly affliction made him unfit to preach to pagan, sophisticated people?

Les explains that Paul must have asked, 'Lord, how can people stand to look at me? How can I stand up and preach to these people when I look so awful?' God's response was that this was precisely when He could use Paul. Les compares this to Moses, whom God placed on the backside of the desert for forty years with sheep—animals that do not smell good—and with no population to speak of. Joseph also made it plain that the brethren should not tell Pharaoh they were shepherds, because a shepherd was an abomination to the Egyptians. Moses, raised in Egyptian culture, could look at and smell himself and say he was nothing but an abomination; then God said, 'Okay, Moses, now we're ready. We'll go to Pharaoh.' Les says the same pattern applies to Paul: he would like to have been something nice to look at, probably a big, handsome Jew like King Saul, but he was not. Yet God told him, 'My grace is sufficient for thee, for My strength is made perfect in weakness.' Thus, in that weakness and fleshly affliction, Paul thought he was unfit to go into those pagan, sophisticated people.