The story goes back to my Math teacher in middle school, let's call her Mrs W. She was a very good teacher but also a true lady, imagine a real life Minerva McGonagall

All my previous teachers got angry when a student pointed out they were wrong somewhere. However, I couldn't resist making a point when Mrs W wrote something obviously wrong on the blackboard.
Her reaction astonished me, though when I think of it now, it tells more about my previous teachers than about her. She looked at the blackboard, thought for a short while, then she said "Indeed, thank you", corrected herself and went on as if nothing ever happened.
It was in such a stark contrast to bouts of other adults when a child truthfully told them they were wrong. Her complete lack of urge to defend her face made her never lose it in the first place.
Somehow it was a tiny, yet very important event in my life.
I've had only one experience like that and it had a huge impact on me too.
Even when things are more balanced (age, authority figure not being a thing) I'm still very wary of people who won't admit they were wrong even when it's obvious or make a huge deal out of it.