Board Thread:Speculation House/@comment-14138255-20140815002519/@comment-75.167.5.96-20140815040929

Correction: we know how Ruby thinks Yang's power works. We also have evidence that she doesn't need to be hit to power up from back in Players and Pieces. When everyone starts showing up at the temple in odd ways, she gets irritated and fires up while stating she 'can't take it any more' and then making a demand for at least two minutes of normalcy.

Which implies Ruby is over-simplifying how Yang's Semblance functions. That the anger generated by being hit (like how a WoW warrior or D3 barbarian's rage meter works, but without Rage being generated by damage caused by the individual) is the actual source of power, rather than the actual energy of the impact.