10 years ago I was really bad at studying, then I had a peak of low self esteem, believing I was not intelligent. Ready to give up uni, my GF suggested I'd give myself only one more opportunity.
So I started studying like it was the very last time I'd do it. Like, in an angry state, like I was demonstrating to myself no matter how hard, it was useless.
This is how I discovered my brain only had a "fast gear", and the "slow gear" that normal people used was basically not working for my brain.
I breezed through all my exams, got a series of cool jobs and promotions, now I own my company and sell my own software to Fortune 50 companies.
The side effect of operating at peak concentration levels is becoming socially impaired, and verbally inept exactly like Chris Marshall above described. This has non trivial social consequences.
The amazing thing here is that I just thought I was getting older and grumpier. But now I understand it's in fact tied to the focus. Thanks Chris, now I know what it is, and maybe I can try to tune it down for a period to see what happens.