And then it turns out we're very much in the same boat.
We're really good at adjusting to these little mistakes, covering them up, because they're insignificant. But we do them constantly...and then forget they happened. I think that most of us overestimate humans' abilities in really mundane matters. We do well, not because we don't make mistakes, but because we recover from them quickly. (And when they're done in a social context, we have rules of politeness that usually allow us to forgive others' tiny mistakes.)
That high evaluation of our own cognitive ability means that an AI that's "less" than that, which makes "silly" mistakes, isn't good enough. Even if an AI makes far fewer mistakes than a human would at some task, any mistake is evidence that it's not good enough, because "no human would have made that mistake". Our meta-perception of our own perception is so clouded by (natural) hubris that we can't even realistically imagine a typical human's performance for comparison.
This, to me, was a great revelation about the human mind when I studied AI: perception is hard, and I'm actually not that good at it. I just muddle through, with some kind of metaprocess smoothing over all these silly little bumps. (And there's an interesting link here, too, to old meditative practices.)