We have never taught any of our children to believe in Father Christmas though some have. One of my sons told me this year how he rumbled the whole thing. When he was around eight years old we took him again to see Santa. Santa said "And what's your name?" "Why do you ask?" says my son "I told you it last year". The lame "Oh I forgot"" cut no ice. The impostor had been rumbled.
Bonhoeffer uses a similar phrase 'worldly Christianity'. It's J Gresham Machen that I want to line up most closely with. See his Christianity and culture here. Having done commentaries on Proverbs (Heavenly Wisdom) and Song of Songs (Heavenly Love), a matching title for Ecclesiastes would be Heavenly Worldliness. For my stance on worldliness, see 3 posts here.