I am lactose intolerant....so milk makes me shit my pants.
My options are to either buy lactose free milk or use the lactase tablets, but even with those I still get some discomfort.
Overall, I love milk in my shake (2 cup milk, 1 cup oatmeal, 2 tbsp PB, 2 scoop ON), but I just can't afford $3 for 1/2 gallon of milk.