DEAR MISS MANNERS: I had a small destination wedding at a nice, but not top-of-the-line, resort. All guests but one had a lovely time. The one unhappy guest usually travels to nicer resorts. We discussed this in advance, and I gave her several opportunities to decline, with the understanding that this may not be her usual cup of tea. She came anyway, but was unhappy and unpleasant the whole time. She spit out food at our cocktail hour, left the reception to eat elsewhere, described the spa as torture, and even insulted my groom and what he was wearing several times. I’m not sure why she wanted…