The document discusses common reasons why sales performance improvement attempts may fail, including: 1) Underperforming sales reps dragging down the team's performance are not being cycled out. 2) The sales team lacks proper training and occasional refreshers. 3) The sales team is unmotivated or has low morale, possibly due to lack of coaching or tension between teams. 4) The sales team is not held accountable for following up with prospects.