Some affection is shown by leaving a person enough room to finish their own thought.

Interrupting is often a form of interest: you can see where the sentence is going, you have something to add, you want to show you understood. What it takes away is the chance for someone to reach the end of their own thinking, which is frequently not where they started. Certain things can only be worked out inside an unhurried sentence.

Let a few pauses go by unfilled this week, especially with people who speak slowly or think as they talk. Count to two before responding. Notice what arrives in the room that would not have arrived otherwise.