Comment by userabchn

I chose an ambitious/important topic for my PhD. Perhaps it is because stories usually have happy endings, causing us to be overly optimistic, but I imagined that if I just worked really hard on it then eventually I would solve it. In the end I did enough to get the degree, but I didn't solve the problem in any real way. It was five years of struggle that didn't produce any interesting results. The biggest learning for me from the PhD was that it made me more humble and caused me to doubt that something is possible unless a clear path to it is already visible.