If you're onstage, performing in the theater, it’s impossible to not matter. No matter how small the role, you need to be giving it 100%, doing what you're doing purposefully and in character, with your costume in place and your makeup perfect. Because if you're visible on that stage, you either improve the audience’s experience or you detract from it. There’s no such thing as a “small part.”
Substitute “customer” for “audience,” and the same thing is true. There’s no neutral in customer service or in creating a customer experience. It’s always possible to improve the experience for customers via your presence, or to detract.