My math teacher was teaching us Trigonometry without ever showing the unit circle, and the class was completely befuddling to me and other students. This was pre-internet, and I stumbled across the unit circle in a book and the meaning of sine, cosine, etc. on it - and was like a huge revelation to me and others.
I've enjoyed trig since, and one of the few math topics I continue to use to this day.
I've enjoyed trig since, and one of the few math topics I continue to use to this day.