the two things I was bad at in school as a kid

 spelling and math.

I remember I got an F on a spelling test in like 4th grade once. And I realized I had to study to not fail. And I was bad at math for a lot longer. Until like 10th grade.

It was because I wasn't open to the possibility of being wrong about the answer I got. There was no check in place. I'd spell the word however I thought it should be spelled and wouldn't question it. Or I'd do mental math and get it wrong and not question it. 

One of my least favorite qualities in a person is someone who consistently says these with confidence that are factually wrong. Like how I was in spelling and math. 

At some point the education system beat it out of me. It said, 'you are fallible. stop believing everything you think. have oversight on this stuff.'

And I think that's a good quality.