Fill a 4-quart pot halfway with water and season, to taste, with salt and pepper. Bring water to a boil. Meanwhile, chop all greens into medium pieces. Place greens into boiling water, remove pot from heat, and let sit 2 to 3 minutes. Drain and let cool. Heat oil in a large saute pan and cook garlic gently until it begins to turn light brown, being careful not to burn. Add blanched greens, vinegar, sugar 2 teaspoons salt and 2 teaspoons pepper.