Outdoor furniture usually looks best when it is larger than most indoor furniture. Of course, outdoor chairs are designed for humans to sit in, so there are natural limits to their size, but the broad arms of adirondack chairs have more value than just as a flat surface for placing drinks on; they also increase the scale of the chairs. This is why they look more inviting in a garden than light folding lawn chairs do.
In flower arranging large flows and leaves are contrasted with small blooms and leaves. The larger element which sets the scale of the arrangement, just as in interior design when the largest piece of furniture in a room sets the scale for everything else. This approach isn't usually as successful in garden design. Large leaves are effective when contrasted against small leaves, but in most gardens you are working on a scale which is set by trees and most small trees grow to be at least 20 feet tall. Large leaves on trees do contrast well with trees that have smaller leaves, but the scale is mainly being set by the size of the trees, not by their leaves.
In traditional Japanese gardens, scale is often carefully controlled, so that a small garden will seem to have greater depth than it does. The easiest way to do this is by having plants with large leaves close to the viewer and use progressively small leaves as you near the edge of the garden. The Japanese went even further by creating paths that became progressively narrower and having bridges in the background that were out of scale with adult humans. Trees in the background were often carefully trained so that they were essentially large bonsai. Such gardens are only effective when designed to be viewed from within traditional Japanese homes or the narrow decks that surrounded them. When an adult gardener was seen working in the garden, the sense of scale would be destroyed.
