One of the first topics in intro syntax classes is the notion of constituency, including a variety of tests which can be used to determine constituency. One of these tests is the co-ordination test: generally only items of the same syntactic category can be conjoined. Thus the following examples are fine: fresh and clean (coordination of adjectives), mad dogs and Englishmen (coordination of nouns [DPs]), (to) serve and protect (coordination of infinitive verbs). But verbs can't be conjoined in the same way with nouns, e.g. *I like mad dogs and to serve is bad; and prepositional phrases don't conjoin with nouns, e.g. *I like mad dogs and on top of the Empire State Building is also bad.
Here's a label I noticed which violates the co-ordination constraint:
*[DP Side Dish], [DP Soup Mix], [PP Over Rice]