Croquembouche is a word that conjures fear in the hearts of many. I've never understood why. Choux pastry is the easiest pastry to make, and toffee is not exactly the most challenging thing to make. Spun sugar can take some getting used to, but it's definitely achievable.
It seems to have stemmed from that MasterChef episode in Series 1 where Adriano Zumbo brought one for the pressure test. Everyone freaked out and it's since been viewed as the penultimate challenge. Many challenges since have been much more difficult, but still everyone dreads the mighty croquembouche.
It's really quite simple. If you've never tried one before, here's a mini version to help you ease your way into it.