Buechner is describing sloth as what I understand as incessant flow.

When we are focused but not aware. This is valuable in some instances (doing the dishes, tedious but necessary work…) but if it becomes a norm, it can derail and lower meaning in life.

The alternative is mindful. Focuses and aware. A mindful person can be seen as lazy sometimes because they take a walk after a complicated phone call. They spend extra time meditating each morning. They don’t rush out of a conversation.

Mindfulness practices has helped me tremendously to not have sloth but occasionally look lazy while bringing my best to those around me.