For manual/wiki lovers, The wiki has been updated with tons of new info!

[Daddl]

All your tile outputs change due to happiness.
A pop working a 1-mineral tile will produce 1 mineral if his happiness is 70%, 0.9 minerals if it's 60%, and 1.1 minerals if it's 80%. And so on in that manner.

Good. Otherwise happiness would really be irrelevant, but that seems to be fine. Then again, I watched for tooltips about this in some videos and couldn't find it.

Maybe I just have to put that in the Wiki myself on Monday

 

[Matto]

Great update !