In my four decades in sales leadership at both large enterprises and early-stage growth companies, and in my subsequent consulting & sales advisory practice, I have witnessed and resolved many poor sales practices. If sales leaders do not diagnose and correct these Deadly Sins of Selling, then accelerated and predictable sales outcomes will be in jeopardy. I recount these sins with amusement since they also tell us something about human nature and how that factors into successful selling practices. Individual sellers, their sales managers, sales trainers, and sales coaches can all benefit from being on alert to these common sins.