Can we live happily?

Certainly yes, but only under certain conditions.
If you do not have basic physiological needs (water, air, food, recreation, clothing, health, etc.) in any case we can say that we live happy, even we can say it does not really living, in the absence of air or water even we can not live.

But only when physiological needs are not satisfied enough. We need space, love the building. We need space to move around us, to have privacy, safety. We need love to share what we have, what we want to have or to share what you do, what we dream. We need love to love life. We need the building, meaning that we need to do something, to build something, anything to stay behind us, do not go through life without leaving a footprint.
Yes! We can be happy, but in certain circumstances.