"Not much" means something very different to a man with a moustache. When a moustache offers his hospitality the responsibility is on his guest to be prepared. Warmth is cherished over politeness, honesty over duty, and decency over obligation. Mr Clean Shaved Fur Collar clearly has not enjoyed being feted as generously by another man. His overly polite response is appalling. He could do much better and engage in flattery.
Rather than supply a mealy mouthed response. Congratulate the host on his generous table. At least our friend has the foresight to look his host in the eye. A Man of Tash is many things but he is no fool. A man with no moustache, unless he has given himself to careful study, must always tread carefully.
Providing niceties might feel like the right option, however understanding always has the greater meaning and is always harder to grasp.