We don't truly "know" anything until we experience it firsthand. Anything else is just a mental image we hold and that isn't true knowing. If it was true knowing then actual experience would be unnecessary, we would just need to hear second accounts of things and think about them.
So the greatest enemy to true knowing is thinking the mental image we have of something is the thing itself.
Rather we need to experience something first hand to truly "know" about that thing!
Sharka Todd with acknowledgement to Kim Michaels.