Most grown people are like icebergs, three-tenths showing, seven-tenths submerged - that is why a collision with one of them is unexpectedly hurtful.
Rumer Godden (2011). “The Greengage Summer”, p.8, Pan Macmillan

Most grown people are like icebergs, three-tenths showing, seven-tenths submerged - that is why a collision with one of them is unexpectedly hurtful.