What term describes those who work unnoticed but contribute significantly to a guest's positive experience?

The term that accurately describes those who work unnoticed but contribute significantly to a guest's positive experience is "back of the house." This includes staff members such as chefs, kitchen workers, and dishwashers who play crucial roles in food preparation and overall restaurant operations. Although their contributions may not be immediately visible to guests, their efforts are essential for maintaining quality, efficiency, and the overall dining experience.

In contrast, the "front of the house" refers to employees who interact directly with guests, such as servers and hosts. While these team members are critical to creating a positive atmosphere, the question specifically highlights those working behind the scenes. The "service staff" typically refers to those involved in the delivery of service to guests but does not encompass the full operational roles found in the back of the house. "Support staff" might include a variety of roles that help in different capacities, but it doesn't specifically pinpoint the behind-the-scenes operations as clearly as "back of the house" does. Hence, "back of the house" is the most fitting term for this context.