Some differences that will affect marriage are family, tribal, cultural, racial, intellectual, ideological nad theological differences. The closer the gap the better.
“I will praise Thee; for I am fearfully and wonderfully made: marvellous are Thy works; and that my soul knoweth right well.” Psalm 139: 14
“For who maketh thee to differ from another?…” – 1Corinthians 4: 7