Why must cashiers avoid personal phone calls during work hours?

Cashiers must avoid personal phone calls during work hours primarily because these calls can create distractions that negatively impact the quality of customer service. When cashiers are engaging in personal conversations, their attention may be diverted away from their responsibilities, leading to longer wait times for customers, errors in transactions, and a lack of focus on the needs of shoppers. Prioritizing customer service is crucial in a retail environment, and being fully present and attentive to customers ensures a positive shopping experience. This focus on service also reflects the values of the company, which aim to foster a welcoming and efficient atmosphere.

The other options don't align with this priority; personal calls should not come before customer service or take up time during work hours, as the primary role of a cashier is to assist customers effectively.