Imaginary Numbers? Seriously?

Okay so it's time to be honest with you. I know that we, as science teachers, like to feel falsely assured either that we know everything or can easily learn anything we don't know.... Far more interesting than what we don't know....is what positively CONFOUNDS us. For example, I always loved math...until I got to college and took engineering-based Calculus. The class was a struggle for me but I muddled through....until I got to imaginary numbers. A number,...that you imagined? A number that could be anything? As in 0, 1, 2, 3, or 9? or as in a group of numbers? or maybe they meant it was a object? This plagued me.

Then, one day, 8 years later, in a Frontier Airlines flight, the zen 40-something surfer next to me simply explained that imaginary numbers are simple,...once you understand that they could be anything, like a variable or equation or constant...at this moment, several lego blocks inside my brain clicked and I realized....all those years of feeling like a calculus failure were unwarranted. It was simply that no one had ever fully explained to me before! To be fair, to do so would have seriously deterred the benefits of early morning alcohol consumption for my tenured Cal professor....and also I think there is still something I'm missing here.

Do you have a similar "bone to pick" with any particular content area? Think back through your education and tell us what stumped you in a certain class. Tell us about it, and maybe you'll have a similar experience.