Having boobs past a certain size has to cause a constant self awareness because of their size and weight that is unavoidable. Obviously some have tolerated the burden or impositions really big boobs impose, but I have to believe that those who actually love having such big boobs enjoy the feelings and mental feedback that are always present. When Allegra walks or or even sits at her piano, her boobs alter the way she does things, what she feels and sees, which I have to assume she finds a degree of pleasantry and warmth in that feedback, their constant visual presence making her proud, like a body builder would glancing down at his arms.