Not all people experience this, especially if they are used to regular massage, but in general you will not feel very good. Your lymphatic system-the system of fluids which essentially clean out your body- would be working extra hard (as a result of the massage) and you would feel like you were getting, or already, sick. In other words you may feel stuffed up(sinuses), achy, very sleepy, possibly nauseous, etc.
It is NOT a good feeling and if you are not used to getting massages then your chances of feeling this way are very high if you dont drink lots of water.
I always push this fact hard on my new-to-massage clients, because the few that dont listen to me severely regret it the next day.