I know the rules of Dark Heresy (and Dark Heresy Second Edition) pretty well.
It's such an odd feeling watching others, who are less familiar with them grappling with them.
I don't know what's really equivalent, because people don't have to deal with me not knowing Dungeons and Dragons like at all. Maybe it's what my group sees when they watch me fail at Pathfinder repeatedly.
Anyways, not a bad thing, it was just very odd.
I'm super excited to watch it tomorrow and hopefully I can use that knowledge to throw page numbers at Geoff should he be taking that stuff from chat.