Waste yarn is usually just a scrap of yarn used to thread through some stitches to put them on hold for a while.
Rows with wraps are a way of shaping a piece, by inserting extra rows in the middle of a row. They can be used to shape the heel of a sock, for adding more room in the bust of a sweater, for adding curve to an elbow, or adding height to the back neck of a sweater, to name a few!
KnittingHelp Queen Bee
"There is a vitality, a life force, an energy, a quickening that is translated through you into action, and because there is only one of you in all of time, this expression is unique. And if you block it, it will never exist through any other medium and it will be lost. The world will not have it. It is not your business to determine how good it is nor how valuable nor how it compares with other expressions. It is your business to keep it yours clearly and directly, to keep the channel open. You do not even have to believe in yourself or your work. You have to keep yourself open and aware to the urges that motivate you. Keep the channel open."
— Martha Graham