Narcissus - Caravaggio
This piece is very detailed and amazing, but the myth you told about is more interesting in my opinion.
I really enjoy reading about mythology, but I also enjoy art, so this is a two in one. 

I do think the myth is the message, just like Hilla pointed out. 
it shows how narcissus is in love with himself, looking at the puddle intensely.
very interesting choice, I really enjoyed learning about the myth behind the painting