What's with all the self esteem songs?

I"m a huge fan of self-esteem.  Don't get me wrong.  I'm not annoyed by aforementioned self-esteem songs.  Just curious.  What started this self-esteem craze in the music industry?

Most of you are probably slamming your heads on the screen in frustration, wondering what the hell I'm talking about.  So, recently I noticed a trend: a ton of songs by popular artists focus on self-esteem and inner beauty.

I think it all started with good ol' Bruno Mars.  Just The Way You Are is a great song about a guy who loves his girlfriend no matter what she looks like.  The kind of thing we all want to hear, right?  It makes you feel nice and warm and fuzzy inside.

"When I see your face

There's not a thing that I would change

Cause you're amazing

Just the way you are"

Next up, comes Katy Perry with Firework, a fabulous song comparing feeling lonely to feeling like a plastic bag.  Yep.  That's Katy Perry for ya.  But it's the thought that counts, right?

"You don't have to feel like a waste of space

You're original, cannot be replaced

If you only knew what the future holds

After a hurricane comes a rainbow"

Right up next is P!nk, or P-exclamation point-nk, as I refer to her, with Perfect (clean version).  It's typical Pink music, but the lyrics are, well, self-esteemy.

"Pretty, pretty please

If you ever, ever feel

Like you’re nothing

You are perfect to me"

And finally, Lady Gaga gets in on the happy-song bandwagon with Born This Way, and I really do love that song.  I'm usually meh about Lady Gaga, her songs are decent and catchy but I don't love them, but I do like Born This Way a lot.  Don't know why.  Just because.
It's not only self-esteemy but also tolerance-promoting.  She sticks in some lines about racial and gay tolerance, which I think is great.  Maybe hearing it from her will help spread tolerance.
Though I do want to point out how much Lady Gaga sounds like Madonna.  When I first heard this song on the radio, I totally thought it was Madonna.  Strange.

"I'm beautiful in my way,

'Cause God makes no mistakes

I'm on the right track, baby

I was born this way

Don't hide yourself in regret,

Just love yourself and you're set

I'm on the right track, baby

I was born this way"

I was debating whether to throw Sara Bareilles' "King of Anything" in, but I;m not sure if it quite fits the pattern.  Maybe...

And that ends all the popular songs I can think of that are following the self-esteem route.  Let me know if I missed any.  Maybe later we can talk about all the marriage songs.  I mean, Bruno Mars, Train, anyone?