I suspect some people are sincere and some aren’t and it’s hard to tell the difference. To an extent I actually appreciate when people feel comfortable at my house. Getting a glass of water for yourself, for example, is not imposing. I wouldn’t want somebody rummaging in my pantry and cleaning it out... but when somebody helps themselves to an item I tell them that I bought for them or they go ahead and get themselves a glass of water or tea... then I like that they feel comfortable in my home and I feel like a successful host. If they’re the first one up in the morning I would rather they got some coffee and made some toast or something instead of just sitting there. Also, I always take stuff with me to other people’s house. Especially if I will be staying overnight. I usually bring some snack items to share with everybody or I make a dish to share.... I’m no expert in this stuff but I figure if I am both giving and taking then that’s the best I know to do.