They cannot discern
Someone may not have the ability to see or understand how God works because they are not saved. When someone is not saved the Holy Spirit of God is not living in them (1 Corinthians 2; Ephesians 1:9-19). Without the Holy Spirit in them, they cannot discern the deep things of God (1 Corinthians 2:10-11).
They are Spiritually immature
Someone may not see God working in the ordinary because they are spiritually immature because they have not grown in their knowledge of God’s Word (John 8:28-32; 1 Corinthians 3:1-9; Hebrews 5:12-6:3; 1 Peter 2:1-5). Without devoting time to learning God’s Word and other things necessary to grow as a Christian, they are unable to notice how God works in the ordinary things. As we become more spiritually mature, we are given the ability to become fruitful in our knowledge of the things of the Lord (1 Peter 1:2-10).