One simple thing about life -- one simple difference if you will -- Muslims must know -- in fact everyone must know -- is this:
We must all live and Work for Allah -- entirely and fully and all the time. For, we are all his fully owned slaves.
We are neither masters of ourselves. Nor are we owned by anyone else, other than Allah.
Even about Prophet Muhammad, Sallallahu Alaihi wa Sallam, we say he was Allah's "Slave" AND Allah's Messenger:
'Abduhu wa Rasooluhoo.
This is a part of our creed, as they say. It makes the difference between whether or not we are really Muslims. We believe it, we are; we don't, we are not.
We should not think of living our lives how we want, doing everything the way we want, and then somehow try and fit Allah into the picture where, when and how we can.
For, we belong to Allah and not to ourselves.
That is the simple thing about life -- the simple difference in life, the simple fact about life, if you will -- that Muslims must understand.
In fact, all human beings must understand.
A lot of the turmoil in the world now -- and always -- is the result of Muslims -- and people in general -- not understanding this, or not fully and completely believing in this, or not fully delivering on and fulfilling their commitment and their pledge to God Almighty.