Why is "happiness" spelled wrong in the title?

It was the misspelled name of the son's daycare. Will Smith's character refers to it several times during the movie, one of which was right before he and his son share their nicknames and the meanings of those nicknames. Also, the name is painted on the front window of the daycare and can be clearly seen at times.

Courtesy of imdb.com

Yah, i realise tht. Luckily i went to wikipedia to see his real pic and bio 1st then only go to watch the mov. So i was quite surprise towards the end of the mov he make a V.I.P appearance.

Just some extra information abt the movie.

Are there any differences between the movie story and the real story?
Here's a few:

The Dean Witter internship wasn't unsalaried, but had a $1,000/mo. stipend.

The internship lasted 10 months, not 6.

Chris Jr. was 18 months old, not preschool aged, when his mother left him with his father.

They were not rejected from a women's shelter; Glide Memorial, where they stayed in the movie and in real life, was a single mothers' shelter at the time.

He did not have to work short hours; in fact he started early and stayed late.

He was a bone scanner salesman, but not self-invested; he quit the job before taking the internship.

Who is the "Rich" in his later firm Gardner Rich?
Gardner added it himself, in honor of succesful broker Marc Rich, who was not involved in Gardner's company.

courtesy of imdb.com