I sliced flank steak against the grain for probably ten years, swearing by it. Then I got the same tough feedback from a family member last summer. Tried it with the grain on a whim and the strips just fell apart in the stew. Couldn't believe the difference.

TEMPERATURE plays a huge role too. My ferment went bad in just a day because my apartment was like a sauna. Now I keep it in the coolest spot I can find.