Like a river I flow, and you’re happy I do in vain. There is no escaping from my course, without causing pain. What am I?

Answer: Blood

More What am I ? with answers

More What am I ?

Look at me one way and I weigh a whole lot; turn me around and you’ll see that I am not. What am I?
Look at me. I can bring a smile to your face, a tear to your eye, or even a thought to your mind. But, I can't be seen. What am I?
Makeup for finger tips. What am I?
Many have heard me, but nobody has seen me, and I will not speak back until spoken to. What am I?
Many people own a copy of me. Without me the world would fall. What am I?
Many shapes, many sizes. Can't be seen, only felt. I bring pain, I bring joy, I bring laughter, I bring happiness. I can tear the mightiest from their thrones, and those who have me are rich. What am I?
Men walk over me but boats go under me. What am I?
More rare today than long ago. There's a salutation from friends written below. What am I?
More valued than gold, more precious than silk. Pouring like wine and flowing like milk. A count’s nightly feast, an offering of war, a pact that is sealed forever more. What am I?
Most people love to use me. You make me glide through the air. Even your dog loves me. What am I?
My first can be found at the start of a letter. My second is the second of second. My third is the first letter. My fourth can be found by a fairway. My fifth is before the eye. My whole is a friend at the end. What am I?
My first half means container. Not a lot of people understand my language. What am I?