Background: I'm a software developer that has worked for 30 years professionally and has used computers for at least 40. Languages and technologies range across pretty much everything popular (and many that were not).
I've always considered myself intelligent to very intelligent. I own lots of books, love learning, etc. So much so that I considered it a deep part of my self-image. Except while attending a very good engineering school, I generally considered myself the smartest person in the room (yes, insufferable, really).
Now, internally (stored in one of those places in your mind that you know are there but you just pretend isn't), I knew this wasn't the case. I have a terrible memory and have always seemed to have to work at least twice as hard in math and sciences and still only had a vague understanding of what was going on. Even to this day I can tell you a lot of findings about the fundamentals of computer science theory but I couldn't explain them to you except in broad sketches. And if you asked me specifics about a book I just read I would likely draw a blank. That said, I've had very successful career as a developer.
Recently, I began playing Go more seriously after playing casually for years with another (much higher ranked) player. I've joined a local group, play online regularly, study books, etc. While I previously thought I was a pretty good amateur I was quickly disabused of this notion. I was beaten handily by almost everyone I played. Worse, studying made almost no difference. This caused me a bit of a intellectual breakdown. It was as if what I always knew deep down was actually true: that I'm NOT particularly smart or gifted. That I'm at very best "average" if not below. Go shined a big, bright floodlight on all of those insecurities that I hide from myself. My entire self-image was shattered.
I'm still picking up the pieces of this realization but over the past few months it has radically changed how I deal with other people as well as how I perceive myself. I think I'm a little more understanding, a lot more humble, and maybe a bit more "human". I'm still a successful software developer, but now when I'm studying something new I'm not doing it out of some misguided belief that learning it will somehow make me better than other people, but because it will make me a better software developer that can help solve problems better. I don't treat knowledge as something that I can lord over people to show that I'm smarter than them. And I seem to assume better of people than I did before.
And I still play Go, poorly.