A dream is like a seed in a number of ways

A seed in hand (not planted) remains
a seed and a dream in mind (not worked
out) remains a dream.

A dream needs a favorable environment
to materialize like a seed needs a fertile soil.

A dream requires time to become
a full-blown reality, same as the growth
of a seed into a tree.

A dream can be choked when surrounded
by wrong people like a seed planted
amongst weeds.

A seed becomes a plant and gives out oxygen,
fruits to people. A dream should be beyond self
but be beneficial to other people.