Without explaining the context of the coffee shop scene, just as a 7 minute showcase of acting, it's incredible. You rarely see that in movies today. The expressions, the tone, writing, the music. It's maybe my favorite scene of pure acting ever. So much backstory and layers in a quick conversation, not a lot of exposition, it's all in the delivery and the words.
the subtle ways their expressions showcase what they are saying. Pacino's subtle understanding and approval when he says "I tell her I'm a salesman", De Niro's laughs almost with just a quick smile at the end, acknowledging the weight of the moment, and it's unusualness. To tell the person you will kill them, but like them anyway.
Now, the movie would have flashbacks, in quickly edited shots of their past traumas or something like that, or a quick edit of one of them trying to fall asleep or something lol