I'm all around, yet I can't be seen. 
And when you're alone, I'm what you feen.
I can make you have joy in chest,
And all through life, I'm the ultimate test.  
I can make you sad, to the point you think you have a disease.
I'm so strong, I can make you so weak in your knees.
Some people mistake me for *** & I can make a male ****** flex.
Once u can identify me, LIFE...start to begin.