Your Mood rating is not determined by the overall mood you select on the first page of your check-in. Instead, it is determined by individual emotions selected on the Emotions page. When calculating your score, our analysis weighs the ratio of negative to positive emotions that you’ve chosen over the last 14 days.

So, how do OK emotions factor in?

The classification of each OK emotion depends on the individual emotion in question. They were not all created equal, so to speak! It is possible to receive a green rating, or an amber rating, or a red rating by choosing only OK emotions. It's what you pick that counts. 

For example:
We recognise that the OK emotion of feeling peaceful should not be considered the same as the OK emotion of feeling worried - and rightly so they will affect your rating differently.