Trust us, you'll want to serve these tender, spicy braised greens with cornbread on the side so that you can crumble it into the bowl to soak up the "pot likker".
Heat a large pot over medium-high heat. Add bacon and cook, turning occasionally, until just crisp. Transfer to a paper towel-lined plate, then carefully discard bacon fat and return pot to the stove. When cool enough to handle, roughly chop bacon.
Add water to pot and bring to a boil. Add bacon, greens, jalapeños, vinegar, salt, and pepper, reduce heat to medium low, cover, and simmer until greens are tender and "pot likker" liquid is flavorful, about 1 hour.