What is it that makes people apt to adding extra letters in words that don't belong to make an exaggeration or look cute?

"yesssss"
"i love youuuuu"
"i'm so excited for tomorrowwwwww"
"omg you have to luv lil wayne he's da best. i luvv lil wayneeeee"

Okay, first off is it not only a PROVEN fact that listening to Lil Wayne makes you dumb (see here) by slurring your words, you really aren't proving a point as to why I should love him either. Granted, even if you made an extraordinary point as to how listening to him will change my life for the better forever, I still wouldn't listen to him. I'd be too distracted thinking how it's possible for someone who looks the way he does to NOT have down syndrome.

And speaking of down syndrome, that's exactly what I imagine the person sounding like with all these slurred words.

I guess stupid is as stupid does.