What rules most grinds your gears? What would you change.
My pet peeve is the quick tap from a scrum (or ruck, maul) where the ref hasn't yet made the mark (as he physically can't as there are a pile of bodies in the way, half of which will be offside the moment play resumes).
This is a scrum penalty for a collapsed scrum:
Look where the scrum is, look where Barnes is going to allow the quick tap to be taken from. Look how many people are offside. It's going to result in either a cheap try, or a penalty, quite possibly a yellow. This is an extreme example as Barnes is too weak to make Picamoles even take it roughly behind the yet to be made mark.
I just love watching cheap-ass quick tap tries, because a collapsed scrum really deserves to be punished by a quick tap taken while half the team is on his face in an offside position.
The 'more correct' modern method of quickly taking it from behind the scrum (E.g. in line with where the ref's mark will be once the ground is cleared of collapsed props) is still bullshit. In my playing days; you had an opportunity to get the majority of your team back onside, as they anticipated a quick tap as the ref moved to make the mark, Nowadays; it results in a minor infringement bequeathing a compulsory professional foul (or at best the ref ignoring the resulting professional foul).
This has grated at me ever since we first started Mextedising the rules.
I reckon this is your legacy Junior Tonu'u and Mextedised refs of the early Super 12.