you guys dont read much riddles, do u...? 
 
I can fly like a bird not in the sky, 
which can always swim and can always dry. 
I say goodbye at night and morning hi. 
I'm part of you what am I. 
I follow and lead as you pass, 
dress yourself in black my darkness lasts. 
I flee the light but without the sun, 
Your view of me would be gone. 
 
its a riddle ive heard before the answer is your shadow. 
and this part:  
 
I am what men love more than life, 
fear more than death or mortal strife, 
What dead men have and rich require. 
I'm what contented men desire.  
 
this riddle is actually in a lord of the rings book. the answer to this is Nothing.