My worst experience ... and best, was when the company I worked for sent me to teach OOAD to the faculty of the Mathematics and Computer Science department of a University in Pennsylvania. There I was, a guy with no degree teaching a group of PhD's the fundamentals of OOAD. Imposter Syndrome? You bet. Nervous? Yes. My mouth felt like it was filled with cotton, and when I picked up a cup of water on the first day, I had to put it back down because my hands were shaking so badly. I could handle a room full of developers, but for me, this was a whole other league. As it turned out, the professors had a blast, and gave me great reviews, but that first day of a five day class was a doozy. After that, I knew I could handle anything.