Glances are another casualty of watchOS 3. While this feature has been removed, you can still get information from your most frequently used apps quickly.
Instead of Glances, watchOS 3 makes it possible to press the side button to see updated thumbnails of each frequently used app in the Dock. These are updated automatically in the background. A long press on the side button initiates an emergency call.
Swiping up on the Apple Watch face no longer invokes Glances, it brings up the Control Center instead.