Measure the unmeasurable

An iPhone app, Mappiness, attempts to measure the unmeasurable, group happiness at specific times and locations. 
This app beeps users at a random time during waking hours and asks them to rate their happiness level and also asks relevant happiness related questions; Who are you with? Where are you? What is the noise, surrounding green space, air pollution like at the instance you are measuring your happiness? 
Mappiness is part of a research project at the London School of Economics. A quick look at the results at show a steady level of about 4 out of 6 happiness units on a Sunday and a level of about 2 on weekdays. 
A spike appears daily at oh, about 5 pm with a curious steady decline until bedtime.
Londoners seem every so slightly less happy than their more rural brethren. And perhaps, based on the following story, there is a correlation with their smartphone brand.