When God works He often does something no one expected. When God promised Abraham a son, Abraham and his wife were well past child-bearing age. One of the times the children of Israel needed deliverance in the book of Judges, God called a poor, unsure man, and pared down the army he gathered to 300 men to chase off thousands of enemies! When God rejected Saul as king and chose another, He chose the youngest boy of a poor family right out of a sheepfold! When God sent Jesus, He sent Him as a baby instead of a full grown man.
Some good reading on the topic of unexpected things can be found in 1 Corinthians 1:18-31. Would you show someone their wisdom is folly by using something that appears foolish to them? Would you use the weak to show the mighty a thing or two? Would you use things and people that are utterly despised to advertise for you? God chooses to do the unexpected for His glory. He is God and He can do anything, and this becomes incredibly obvious when someone severely lacking qualification and skill ends up doing the very things they couldn’t! Let’s also note that the God who created the vast intricacies of the universe can think up any plan!
There are many other places in the Bible that tell out the unexpected plans of God. The way the accounts go, it seems to me that one of God’s favorite things to do is confuse and surprise, showing how awesome, powerful, loving, and good He is. Doesn’t that just fill you with joy? Expect God to do the unexpected in your life, and even then you’ll be surprised!