Blood = family (though not necessarily related by blood, such as husband and wife)
Water = non-family
2) A man wakes up from a coma to find all of his family around him. Man: "Where are all my friends? They said they would be there for me no matter what!"
Nurse: "I suppose it's true what they say: blood is thicker than water."
3) "Why did this man's friends show up to his funeral, yet none of his family did?"
"Well... I guess water is thicker than blood!" (the opposite can also be used for dramatic effect)
person 2: um........ u gon on without me i wanna chill with my friends
person 1: hey cuz i really don't like one of your freinds, she was being a bitch
person 2: omg how could u say that about my friend, she is such a goood person, u probaly pissed her off or something.