A sight or an action that catches my eye. It can be anything around me or any thought triggered by something someone says or does. I think we just have to be sensitive and aware of the world in general.
I suppose things closer to home have more influence; family, friends, the garden, wildlife. The joy of living and the emotions that accompany it are the main factors.
If you want a root influence, then that's my Dad - he wrote plays, poems, articles and had a wonderful sense of humour.