The genetics of a person plays no role in his choice of the color of his shoes on any particular day. The choice of the color of shoes a person wear is dependent on a number of factors, but his genes have no role to play in that choice. Thus, the choice of shoe color of any particular morning has a heritability estimate of 0 %. The genes determine a lot of traits of a person's personality, but the choices of day to day life are a different story.