One book that I consulted gives this advice: "Only subjects that are closely allied can reasonably be construed as a unit." So -- as the other members have said -- it would be fine to use either the plural or singular, for many people would consider the food and the service to be "allied" (combined or connected). On the other hand, it would probably be better to say: I am never going to that restaurant again. The parking arrangements and the food WERE horrible.

This is mostly a matter of usage. "Were the food and service OK" is more grammatically correct and it is still in use today. However, it has become more common to view "food and service" as a single item, a package, hence the use of "was". For the same reason, you will say "the surf and turf was delicious" or "the hustle and bustle is concentrated in the heart of the city".

One would think that "were the food and service OK" would be correct, because you are talking about two things. But really, people almost always say "Was the food and service ok." They would say "were" if "service" was plural. I hope this helps!

I would say "was the food and service ok" because you are talking about single items not plural even though you have two items "food and service".