Characters
You can’t express every feeling you have every moment that you have them.
— Sally Albright ‧ When Harry Met Sally...

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
Sally is pointing out that feelings don't all need announcing. Having an emotion is one thing, and voicing it constantly is another. It's an argument for some restraint, keeping a little back instead of pouring out everything.
Context reviewed