Question: Due to impermanance of everything, Are there anything to be happy or sad about ? Even about **dhamma** ?

If something seems like to be happy, there are some reasons to not to be happy.

1. It is impermanant for sure. but also,
2. That **happiness make sadness in the future (future includes next lives)** (I need to be sure about this sententce, please mention about this in your answer)

Are enlightened people happy ? Or neither happy nor sad ?

Answer: 
**Are there anything to care about in this universe?**

Yes, you should care about other sentient beings and practice putting their well-being foremost in your mind. If you have no experience with this, then try [practicing the four immeasurables.](https://thubtenchodron.org/meditation/03-prayers-practices/01-recitations/four-immeasurables/)

**Due to impermanance of everything, Are there anything to be happy or sad about?**

Rejoice in other's happiness! Rejoice when other's wishes come true! Rejoice in other's sorrowless bliss! Rejoice in other's progress on the path of dhamma as this is the hope of the world!

**That happiness make sadness in the future (future includes next lives)**

You've got it completely and totally wrong friend. How can happiness make sadness in this life or in the next? The problem is sentient beings don't know what happiness is or how to get it. We chase after things that *do not* lead to happiness thinking they will and we shun things that *do* lead to happiness thinking they won't. We are like a dog tied to a pole and wound round-and-round... we pull harder and harder to get free, but only succeed in binding ourselves tighter to the very thing that makes us miserable. We are quite silly and ignorant.

**Are enlightened people happy?**

Of course! They are immeasurably happy. Indescribably happy. Happy to such an extent that it is impossible to conceive. How do we know this? Because in order to become enlightened they must work for countless lifetimes at accumulating and working at the causes of happiness! They must perfect all virtuous conduct! They must perfect all virtuous minds! Take them to their zenith! Imagine a mind as wide and deep as the ocean filled with the most altruistic and peaceful thoughts. With absolutely zero ill-will and focused on other's well-being to the limit. Such a mind... we cannot even begin to describe the happiness it entails!!

**Or neither happy nor sad?**

You need to work on discovering what happiness is and the causes and conditions of happiness. Fortunately, that is exactly what the dhamma teaches. Your confusion is caused by misunderstanding. Rest assured you have it blinkered, but keep working at it and working at it and working at it... don't stop! and you'll slowly unwind that leash holding you to the pole. 

Dhamma is the Ultimate Medicine. Buddha is the Ultimate Doctor. The Sangha are the Ultimate Nurses.

The disease is dhukka and unhappiness. The cure is happiness... immeasurably so!
A few comments on happiness...

“By stilling thought one kills
Both good and evil deeds:
Self-stilled, abiding in the Self,
One wins unalterable happiness.”

Maitri Upanishad

“People often suppose that the realization of nirvana means the annihilation of all forms of existence. This is not true. What really transpires is that the illusions arising from our ignorance are extinguished, and we know true happiness, independent of any causes or conditions. And we continue to exist.”

The Dalai Lama - *Reflections from the Journey of Life*

“…[A]ccording to Aristotle, ‘it is necessary that there should be an eternal unchanging substance’ (Metaphysics 12, 6). This will impart change to other things, but will not itself change. Moreover, it will be immaterial, since it is beyond any sort of change or corruption. … It cannot itself change, because all change would be for the worse. And it contemplates the most perfect and best of things, and so exists in pure bliss or beatitude. What is the most perfect of things? Well, it is, so it must be thinking of itself. So God enjoys contemplating the divine being itself, knowing that it is the best thing there is. ‘Its thinking,’ says Aristotle ‘is a thinking on thinking.’ That is, it is the object of its own knowledge, and in such knowledge lies supreme happiness.”

Keith Ward - *God: A Guide for the Perplexed*

“It is possible to live in a state of stable happiness only when we are completely free of ignorance. Awakening puts an end to unconscious rebirth, and then the conditions and causes of painful effects disappear. This is the realization of a state of happiness which no longer depends on our external circumstances, nor on our emotions.”

The Dalai Lama - *Reflections from the Journey of Life*