Part of my job is to arrange coffee and lunch for visitors, make coffee for the directors. I always make sure each cup and saucer has a spoon with a separate spoon for the sugar bowl. One of the directors puts sugar in their coffee, stirs then puts the coffee wet spoon back into the sugar bowl completely ignoring the spoon on the saucer. Maybe I need to lighten up but I do find that annoying.
Funnily enough 'sachets' are one of the little things which annoy me. I don't particularly mind sugar sachets but its those sachets of tomato sauce, mustard, mayo etc. Not only are they difficult to open they leave a mess in their trail - torn open used sachets on the table top. Horrible!