Final answer:
Crossing your arms while talking to a customer is an example of negative nonverbal behavior in a service setting, as it can convey disinterest or hostility.
Step-by-step explanation:
An example of negative nonverbal behavior directed by a service provider to a customer is B. Crossing your arms while talking with a customer. This type of body language can communicate disinterest or even hostility, which may make the customer feel unwelcome or uneasy. In contrast, options A, C, and D (gesturing with a flat palm, avoiding the use of a disapproving facial expression, and a firm handshake) are typically considered positive or neutral nonverbal behaviors. A service provider should be mindful to maintain open body language, such as uncrossed arms, and use positive facial expressions to convey friendliness and openness. Nonverbal communication is a crucial aspect of customer service, and negative gestures or expressions can have a detrimental impact on the customer experience.