Half is better than none

Eileen danced on, unaware that half of Bob had become detached (again!) while they were walzing to the Blue Danube.
Debbie checks her magic charm bracelet. Is it time to restore Bob's missing half? No, she'll wait to the end of the dance, when it's her turn to waltz with Bob.
(If disembodied dates don't bother you, find the pattern here.)