A person views the situation optimistically or hopefully. For example, Betty was not upset by the last-minute change, since it gave her extra time—she always sees the glass as half full. The opposite—that is, the pessimistic view—is put as the glass is half empty. Also see bright side.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.