The Pursuit of HAPPYness, why

[JoolsToo]

is it spelt like this. 'Happy' is differentiated in the title (shown in red) but why?

Why just not 'happiness'?

Any clever bod know?

It's driving me bats (thinking of all the little kids who are going to start misspelling it!)

Fantastic film- went to see it on Saturday night and was still choked up on sunday morning. xxxx Loved it!!!

Will this be boring for a fairly blokey bloke? I'd like to see it but he thinks it's a chick flick.
Alternative is Last King of Scotland, which would you recommend?

It's not very fast moving but I thought it was watchable, I liked the bit where the little boy asked if 'Fu*k' was spelt wrong on the mural too