Although our universe may seem stable, having existed for a whopping 13.7 billion years, several experiments suggest that it is at risk—walking on the edge of a very dangerous cliff. And it's all down to the instability of a single fundamental particle: the Higgs boson.
Maybe the idea that there was even a “dangerous cliff” in the first place was wrong. Metastability events remain purely hypothetical in the same way that stable strangelets are.