Valkyries and acting misconceptions

How often do I speak on stage or in film thinking I know what I am talking about when I really don't?  Often!

Delivering a line with conviction, even though I have the wrong understanding of what it is I am talking about.

I noticed this today when I was reading about Valkyries, they aren't what I thought. They are sort of angels instead of the viking-type warriors I had in my head.

Note to self- don't assume you know everything, and it doesn't hurt to double check those things I think I already know.