After about 4th grade my schooling was a disaster; I had tons of issues and was considered an underachiever, so I never really considered myself smart. I only allowed the idea that I was a gifted adult after struggling to grasp my first daughter's gifted issues. I was struck at how much she reminds me of myself at her age, even down to having a precious companion toy friend with her at all times.
One problem I have suffered from my entire adult life is impatience in conversations, especially meetings. I agonize waiting for people to finish what they say because I catch on very early knowing what they're going to say. Group discussions are particularly difficult, where people seem to enjoy the creeping pace of approaching an insight or conclusion that was obvious to me long ago.
This feeling has never made me feel smarter. Until recently it never occurred to me that other people were not doing this inside too. I just figured that most of the world enjoys blabbering on and sneaking up on their conclusions, and that I was somehow defective in that regard. I squirm and feel restless, falling back on my imagination to make the topic more interesting, usually by blurting out left-field analogies that others usually find humorous if not jolting. If I were a more articulate speaker in general I might thrive in these situations. This might be giftedness, or it could just be my ADHD. If I think back on it, I can recall having that same feeling in classrooms too.
I recall a while back I was trying to install a lesson in DD by explaining why she was being disciplined. She squirmed in frustration and cried out, "I know what you're going to say."