Simple to make, simple ingredients. Every household has their own version of this recipe, every one. Passed down from grandmothers to mothers.
In a community of 500 families not one recipe has the exact recipe, there's gonna be a defining taste.
I lived away from home half my life and had girlfriends who knows how to cook adobo. Several years forward I'm single and missing adobo, so I tried this Filipino restaurant that serves Pinoy dishes, one of them is Mr. A (adobo). It was delicious and expensive. Around 10 dollars US a plate without rice.
Then I tried experimenting, a little of that, more of that. Fail. More on vinegar, little on soy sauce. Fail. Fail. Fail. Fail. Until I met YouTube.
Fast forward, let's cook. Pork belly (cut into bite size), Garlic, onions and pepper. Heat oil then add garlic, onion and bay leaves. In a minute add pork then pepper. Half fry pork until sides are brown then add water (don't drown pork) and let boil until pork is tender. Once tender add soy sauce for color and flavor (taste it according to your preference) finally add vinegar (lesser amount than soy sauce). Cover till vinegar is well mixed with everything, do not lift the lid, you'll know because it'll send exploding umami smell.
If your curious, follow the instructions. You might get it the first time and like it.