Writing haiku is wonderfully relaxing. (I need to take it easy after all that hard work on the sestina.) I don't know what it is about the combination of 5, 7, and 5 phonetic units that is so serene and peaceful. But you'll notice that writing haiku is good for the soul.
I discovered that there is a difference between the original Japanese form of haiku poetry and the Western version. In Japanese, the haiku contains a special season word (kigo) representative of the season in which the poem is set, or a reference to the natural world. The three different phases are signaled by grammatical breaks, and the poem is written all in one line. In English, we generally separate the poem into three lines.
I'll get you started with two beautiful representative poems. The first is translated from an "old master" Japanese poet. The second is a more modern, urban haiku.
Temple bells die out.
The fragrant blossoms remain.
A perfect evening!
--Matsuo Basho
Freeway overpass
Blossoms in grafitti on
fog-wrapped June mornings
--Michael R. Collings