While it is considered normal for teenagers to write in a round style, adults who do so can tend to exhibit traits of immaturity, naivety and dependency in their personalities.
Round style writers are flexible and yielding. They tend to prefer compromise to argument. When issues concern their home and family, they are possessive and jealous and will fight for those who have their sense of security threatened.
Round style writers tend to be emotional and physical. They tend to find more fulfillment in the real world of experience than they could in the abstract realm of the mind.
Source: Hand Writing Analysis by Karen Amend & Mary S. Ruiz.