Bored.

Lots of characters are bored.

People get bored. You get bored. I get bored.

Some scenes the two characters are just passing time. That’s their action. Their objective is to be happy. They get happy by hearing the sound of their own voices. 

They’re bored.

Iconic types in procedurals get bored doing the same job day after day and week after week. So do the actors who play those roles. Saying the same kind of lines episode after episode.

It can be useful and isn’t pejorative.

It’s useful to you as an actor to have boredom as part of the base you’re working from. Boredom creates a hum in your brain that can settle you, calm you, or, sometimes get you rattled. All useful qualities to add to your actions in the scene.

Boredom is a great antidote to doing too much.

Guard against putting so much effort into every scene trying to be a good actor. The state of being bored is deceptively active.

Any repetition of activity over a long period instills boredom.