KK's are so sweet... that if you eat cake after, the cake will taste sour. Same goes with any soda or other desert.
KK's are overated in my opinion, too. At least at Dunkin Donuts, when you get a donut and coffee, you feel you have eaten something partially decent. KK's taste like you ate chemicals engineered to taste like you just ate one dozen donuts smashed into one donut.
I eat KK's one in a while, though.. because they are the only donuts on campus.