I'm not in retail anymore, and I never did clothing retail, but working in theater costuming has really changed my ideas. Like, I know I am fat because at my height and weight my bmi puts me well in obese territory. But measuring people a few inches taller has put an interesting spin in my head. I know someone with the same bust size who is three inches taller and now I understand why some "large" sizes will fit both of us even though by size my cup is several sizes larger than her.
People have been telling me for years that I'm "not fat". I know they are delusional because of the numbers, but seeing other people with similar measurements does actually put it into perspective.