No, I don't think I've ever done a 20% hill. 19%, yes for sure.

"Steep" is stuff that I haven't even tried. I was just toning down the magnitude in an effort to defuse the guys who'll pipe up and say "yo moron, 18% isn't steep unless you're a wimp, 25% is steep!". To me 16% is steep, else I wouldn't have pestered my friend on what gear to use on such a hill (remember he said a 53x15 - that's not a gear you use up a steep hill, in most cases, and this conversation took place when we were 14 and 15 years old). 19%, there's a short little hill near Nytro and someone next to me said his Garmin said it was 19% - for me it's short enough that I'd rather 53x15 the thing than 39x25 it.

I've declined rides where they planned to hit hills over 20%, like 22% etc. I don't see the point in climbing such hills. Those are "really steep" hills to me, the ones I prefer not to do.