Above is a photograph of a single red leaf. It is on a vine that is on an oak tree. Although the image is bright, it has a somewhat darker idea underneath.
The leaf is red, not because red is bright nice color, but rather because the leaf is dying in the winter. The vine is losing it leaves.
Additionally, the vine is using the oak tree. Although the vine benefits from the structure of the tree, it is to the detriment of the tree.
This idea, of something that seems bright in meaning having a darker underside, can inspire poetry. Here is an example poem:
for the party
he put on
his knight costume
little did he know
though not all in on the joke
would be dressed normally