“As we were riding through the city [Cracow], I imagined it was the town of Bethlehem. As I watched all those people hurrying about, I thought: who is meditating today, in recollection and silence, on this inconceivable mystery?” (Diary, 844)
I think it has more to do with us distracting ourselves with worthless things that pull us away from the Lord (chatter.) In the above example, we can see that St. Faustina is wondering who of the busy people take the time to meditate “in silence” about the birth of the Lord (it was near Christmastime.)
Also: “My room is next to the men’s ward. I didn’t know that men were such chatterboxes. From morning till late at night, there is talk about various subjects. The women’s ward is much quieter. It is women who are always blamed for this; but I have had occasion to be convinced that the opposite is true. It is very difficult for me to concentrate on my prayer in the midst of these jokes and this laughter. They do not disturb me when the grace of God takes complete possession of me, because then I do not know what is going on around me.
My Jesus, how little these people talk about You. They talk about everything but You, Jesus. And if they talk so little [about You], it is quite probable that they do not think about You at all. The whole world interests them; but about You, their Creator, there is silence. Jesus, I am sad to see this great indifference and ingratitude of creatures. O my Jesus, I want to love You for them and to make atonement to You, by my love.” (Diary, 803-804)
We can see that these men constantly chattered about everything but Jesus, which led St. Faustina to doubt they thought about and appreciated Him very much. So the moral of the line you quoted above may be to not be so preoccupied with worthless chatter and everyday stuff that we forget to take time of interior recollection and spiritual communion with God through prayer and meditation.