Not every noun benefits from a relative clause. In general, words that are vague are more likely to need the help of a defining clause, whereas words that are more specific tend to be strong enough on their own, especially when paired with a regular adjective.
In the attached activity, low-intermediate and intermediate students can develop a sense of when and how restrictive relative clauses work to clarify and focus meaning.
Time: about 20 minutes
Materials: copies of the attached activity, one for each pair of students.