A monk asked the Chinese Ch'an master Chien Paling:
-What is the difference between the meaning of the Sutras and that of the Patriarch?
The master replied:
-When it is cold, hen would go up on a tree and duck down to water.
I don't think happiness and suffering can mix together. The absence of suffering is happiness and likewise the absence of happiness is suffering. You can be in pain yet you are still happy. Pain per se is not suffering. But you can suffer due to your pain. You can also suffer without pain.