Oregano Is Not One Flavor
Same name. Different plants. Different dishes.
Oregano gets treated like a single pantry staple. In practice, it behaves like a family of flavors.
Mediterranean oregano tends to be piney and herbal. Mexican oregano leans citrusy and more assertive. What many people call Italian oregano sits somewhere in that Mediterranean family, but the jar still matters more than the label on the recipe.
If a tomato sauce tastes vaguely wrong, or a taco filling feels off even though the spice list looks right, the oregano variety is often the quiet culprit.
Match the oregano to the kitchen you are cooking in, not just the word on the page.