Is it possible to get so much utility from a good that it turns into a bad? If so, please give me an example.

In economics, a consumer's utility is defined as the amount of satisfaction a consumer gets from the consumption of a particular good or service.  It is certainly possible to get "too much" utility from a given good or service.

Consider, for example, an all-you-can-eat buffet restaurant.  When you go to such a place, you want to get the most out of your money, right?  But what happens if you go overboard?

In that case, you are getting so much utility from your good (the buffet you paid for) that you overdo it and get sick.  At that point, your "good" has become a "bad."