I think most people use facebook to highlight the best parts of their lives- because most people want to share good news and flattering pictures. It's not an honest representation of their whole lives. If it were, everybody would seem really depressing and boring
Example:
I'm always tempted to defriend an old high school friend- she got an amazing job right after graduating from an Ivy league school with a 3 Bachelors degrees, lives in Hollywood, and spends a lot of time yachting, traveling to places like Miami and Paris, and drinking martinis.
She has a lot of things in her life that I don't. And it makes me hate her.
But, I'm sure she has days where she's hungover and her boyfriend won't answer the phone and she's broke and her boss is pissed that she's late so she feels terrible. And I'm sure she has some deep dark secrets that don't make it onto the internet. Because everybody does.

It's really tough for me to remember that, but it's true.
Personally, my facebook is hardly an honest representation of myself.