Honesty is such an integral part of all relationships...be it personal or professional.
Why do some people feel the need to "expand" on that which is true? Are they afraid that the truth will upset you or make you think less of them? Are they afraid that the truth will damage a relationship? Wouldn't the relationship be it personal or professional be damaged if the truth was discovered? Wouldn't you rather have someone be perfectly upfront and honest with you than find out a month, a year or more later that they have not been so honest with you?
Imagine the foundation of a home...without a strong building foundation - it is unlikely that the home will be safe and secure. If a relationship is built on a strong foundation of honesty - then the relationship will indeed be strong and safe as well.