excuse me, but if i might be so bold, ive been working with pokemon happiness ever since i started playing pokemon. this is all my experience and some that ive gotten from others.
To be fair, it almost looks exactly the same as Bulbapedia or Serebii (I forgot which it was.) beside this part:
When pokemon walking behind you say:
<pokemon> is playing happily while looking at you
Woah! <pokemon> suddenly hugged you!
<pokemon> is poking your belly.
<pokemon> walks aside you proudly.
<pokemon> is just very happy to be with you.
<pokemon> wants to play.
That actually is useful. Would be great if you found out what the happiness numbers were for these statuses but that is near impossible.