I was brainstorming for a new company name with my brother and Dad; and feeling the need to come up with "good" names. I was the one producing nearly all the suggestions. After a small number of names, I stalled. I was feeling the strain of getting it right and not appearing stupid.
My brother said, "No black hats." (He was referring to Edward de Bono's six thinking hats.) To me, this meant that my ideas were not going to be shot down or judged.
I immediately felt the invisible burden lift and the creative flow was released. Sometimes it's so good to be given permission to go for it.