There is no such thing as a perfect investment -- all stocks come with trade-offs. But some trade-offs are just too extreme to bother with.Many ultra-high-yield dividend stocks fall into this category. Contrary to the safe-and-steady image you may have of passive income investments, an unusually high yield can be a warning sign. That's the story behind Annaly Capital (NLY 0.36%) and its gargantuan 13.5% dividend yield. Most dividend investors should avoid it, and for very good reasons. But for Bank of Nova ...