While we don't offer afternoon refreshments or snacks, I do advertise and supply a different dessert each evening. This has been a huge hit with guests, and many say that when choosing where to stay, that little goodie tipped the scale in our direction. Many of our reviews and journal entries mention dessert.
We also have a guest fridge stocked with bottled water and hot water beverages (coffee, about 100 kinds of hot tea, cider and hot chocolate) are available 24 hours per day.
If you have refreshments or desserts that don't get eaten, don't be afraid to freeze them. Most items thaw in just as wonderful condition as they went in. Last week I made a carrot-pineapple-pecan cake with whipped cream cheese frosting, used six pieces for guests and put the rest in the freezer. Yesterday, I pulled the frozen cake out in the afternoon, and it was perfect for evening dessert. EVERY single guest was singing about the cake at breakfast and two of the three ladies at the breakfast table asked for the recipe "best cake I've ever had, so moist and delicious".
Cakes, pies, cookies, cheesecake, brownies, all of these things freeze and thaw wonderfully. If you're not comfortable serving guests something that has been frozen (which I think we pretty much ALL do at least once in a while), then save them and donate to a bake sale or use for a family gathering. Or, send guests off with some of your wonderful brownies or cookies when they depart. People are tickled to get a couple of cookies each for the drive.