When I was younger I quit drinking milk because it made me tired, lethargic, sometimes even made me sick. So I haven't been a milk drinker for close to 15 years.
On my current diet though, whole milk is some amazing stuff:
Insomnia has been a recurrent problem for the two years I've been on this diet, but since I started drinking milk, I have no trouble getting to sleep at all and feel a lot more recovered after I sleep as well.
General anxiety issues are also pretty much eliminated.
Cheap and easy source of extra protein and fat.
Surprisingly high in potassium and magnesium, which are really hard to get on this diet and yet so essential.
12g of carbs per cup, which is low enough to prevent going out of ketosis but high enough to replace my other sources of occasional sugar.
Basically, it's a great counterbalance to all the restless high-energy stuff this diet promotes. Wouldn't recommend it on a standard low-energy diet though.