Maybe I'm really intolerant of people's fussiness, but I would be annoyed if I had a person over to dinner, made quite an effort (as it sounds like you did) to accommodate particular tastes and desires (ie healthy etc.) and they left behind large amounts of food for no good reason. It's one thing to not eat much and explain to the host/ess that you're just really not hungry or not feeling well, or to really not like one particular thing and leave it to the side, another thing entirely to leave most of the meal. Actually, I also think if a person REALLY doesn't like something, they should have the responsibility of letting the host know in advance

Some have said here to see the meal as a gift, well, I always express gratefulness for a gift and I think it comes across as quite ungrateful to not eat what is provided without at least explaining why. Would you just throw a gift that you were given, and didn't like, in the bin in front of the giver?

Sorry, a bit of a rant - I don't know why this gets me so much?