Huntard Corner, Northrend Horde Questing Division

There's a Howling Fjord Hordeside quest, "Green Eggs and Whelps", in which you apply a poison to proto-drake eggs and reap the results. If you have a pet out, you must put it in passive, because otherwise it'll attack the egg while you're spraying it, and that attack ruins the spraying. I went from 0% successful hatchings to 100% when I found this out.