In very many things we don't know how much we don't know. This is true for fluid situations like negotiating a business contract or offering help to somebody in need.
It's also true for objective truths in science, medicine, law, math, etc...
Usually, we don't know how much we don't know. (But we assume we're very well-versed in most things!)
The key is to understand and accept that and approach new situations with openness.
We don't want to ask questions to confirm what we think we know, we must find ways to get to the bits we don't know. Jump into the unknown and risk finding out something new.
Don't be blinded by what we know guiding us into never learning anything new.
We must remain as flexible as possible in fluid situations and when learning new things. Open and fluid is a recipe for success.