What can an adjective describe both of?

This is a fun word puzzle! Here are a few categories of things that an adjective could describe both of:

* Objects: A red car and a red apple.

* People: A tall man and a tall building.

* Concepts: A difficult math problem and a difficult decision.

* Feelings: A happy child and a happy ending.

* Places: A quiet library and a quiet forest.

Let me know if you'd like some more specific examples, or if you have a particular adjective in mind!