Separate collard and kale leaves. Remove and discard the stalks.
Place the bacon in a skillet over medium heat and cook until the fat is rendered and the bacon is halfway cooked.
Add the garlic to the pan and cook, stirring for another minute.
Add in the greens. Start tossing the greens gently with tongs adding vinegar as you toss them. Season to taste with salt and pepper. Serve when they are halfway wilted.