Is it totally normal for a young man to have lots and lots of dark, thick, dense body hair almost all over his entire body?

You're fine: In fact, plenty of other men will be jealous. It's not a sign of any illness -- it's your genetics. Some women prefer a hairy man, others a smooth man; smart people like a man for who he is. You're likely to have early male pattern baldness, but you can also have fun with your body hair, like the dad in the photo. Life's too rich to fret about too much or too little body hair.