Absent-Mindedness
This is a sin against good manners which cannot be too greatly condemned, being, as it is, in some measure an insult to the company in which you find yourself. No one cares to be of so little importance as to find the person addressed totally oblivious of his presence or remarks, and no one can blame him if, as Chesterfield suggests, “finding you absent in mind, you should speedily find them absent in body.”