I'll hope the misdiagnosis isn't missing a serious illness, and even then since I know up front what the catch is I could just get a second opinion every time. Unless no matter what I'll never get a correct diagnosis. But still, I'll hope whatever I have isn't serious and take the money.
A million dollars but you no longer need to eat or drink, and also can not consume any food or drink either. Feels simple but I imagine it could become really torturous to never eat or drink again. Also have fun taking pills without water.