If the service is bad but the product is great I would overlook the service unless it was consistently bad in which case I would have to decide if the great product is worth overlooking the service. Also is the product available at other locations of either the same establishment or a different establishment but same product.
Ex #1 product is a Griffin widget (Not food) at Lowes on Main St. The service sucked but we know how great the Griffin widget is. I could try the Lowes on Smith St to see if they have better service or as Home Depot also carries Griffin widget and has better service just go there.
Ex #2 product is a NY Strip Steak at Texas Roadhouse on Main St. The service sucked but we know how great their NY Strip Steak is. I could try the Texas Roadhouse on Smith St to see if they have better service or as Longhorn Steakhouse also carries a NY Strip Steak and has better service just go there.
If the product is bad but the service is great I would go a different way depending on if the product is food or not.
Ex #1 product is a Flash widget at Home Depot. I find it is absolute junk. The salesman was great very knowledgeable and helpful. I could see if there is a comparable widget that is better, which is how I found Griffin's widget or decide that despite Home Depot's great service they only carry junk and not go back.
Ex #2 Product is a Beef Wellington at Mom and Pops Steakhouse. I decide that it tastes horrible but the server was very accommodating and provided stellar service. Lets assume this is the only thing I like on the menu. I am not going back. If their were other items I liked and being a shop allowed to order then due to the service I would go back unless I found all their food to suck. I would then decide to go elsewhere. I decide to go to Gordan Ramsay's Steak as I really want a good Beef Wellington.
Note: I just chose business names and products at random and are not saying they are good or bad in real life.
Shopping Western NY, Northeast and Central PA, and parts of Ohio and West Virginia. Have car will travel anywhere if the monies right.