When I feel I'm having a bad day or something doesn't turn out to my liking I try to remember the following story.
There is a Taoist story of an old farmer who had worked his crops for many years. One day his horse ran away. Upon hearing the news, his neighbors came to visit. "Such bad luck," they said sympathetically.
"May be," the farmer replied.
The next morning the horse returned, bringing with it three other wild horses. "How wonderful," the neighbors exclaimed.
"May be," replied the old man.
The following day, his son tried to ride one of the untamed horses, was thrown, and broke his leg. The neighbors again came to offer their sympathy on his misfortune.
"May be," answered the farmer.
The day after, military officials came to the village to draft young men into the army. Seeing that the son's leg was broken, they passed him by. The neighbors congratulated the farmer on how well things had turned out.
"May be," said the farmer.