With hiring, certain candidate weaknesses are harder to see. It’s not that you’re not trying to see the whole picture, but you under-investigate particular traits. Maybe you favor candidates that closely share your values and strengths. Maybe they remind you of yourself -- and after all, you’re good enough, you’re smart enough, and doggone it, people like you.
Every blind spot is unique.
I am often blinded by highly empathetic people, those people with high "emotional intelligence" -- if they connect with me, I tend to overlook certain missing skill proficiencies. It’s not that I don’t know how to interview for skills, but it’s easy for the halo effect to take hold. If not kept in check, I start ascribing skill proficiencies because of a candidate’s emotional intelligence.
Likewise, some managers routinely overvalue credentials like a prestigious degree. They might gloss over questions that prod at that intelligence, assuming the intelligence is there. Why focus on it when the candidate’s alma mater is Yale?
And that’s why blind spots get you into trouble. You tend to make the same mistakes over and over, but your brain glosses over why. Unless you have a system in place to check yourself (a recruiting partner to watch your back), you’ll experience hiring failure after hiring failure.