I never saw my rock history class instructor get upset when a student wasn't paying attention. Instead, he'd address his concern politely to a student sitting next to the offender. With no rancor in his voice, he'd say, "Excuse me, would you please wake up the person sitting next to you? I don't want him (or her, but usually him) to miss this next point."
I thought that was considerate. After all, students shouldn't be sleeping through a lecturer's explanation of how the title of Jefferson Airplane's song, "Volunteers," is ironic.
