To me, haiku is like witnessing a scene where two persons are standing at some distance while a third one is looking at them. This third guy says something very interesting about the two that is appropriate, curious, sensational, fantastic, wonderful, exciting, marvelous, enlightening and so on. You can put things in place of persons and as a poet express in a similar style but no metaphor, simile, exaggeration should be used. There must be three lines in a haiku. GThe expression should be too obvious in simple words leaving a great impression on the mind of readers. The season aspect is not necessary that was used in the original traditional Japanese haiku. This is all what I have grasped about this great art of poetry till now.