Brent crude was flirting with $110 just last week. Now it's clinging to the $100 level.

That's a 10% drop in days. Oil markets are jittery — demand fears, China slowdown whispers, or just profit-taking after the rally? Hard to say.

But here's what matters: energy costs feed into everything. Your groceries, your commute, your inflation expectations. A sustained drop here would be disinflationary. A spike back up? Pain.

Watch this. It matters more than most headlines.