A member called V4nKw15h wrote this on Quality of Life:
"Firstly, the issue of quality of life has been covered in great detail in my city journal along with just about every other area of the game as far as how the underlying simulation works. It is a big read but well worth the effort if you want to understand how things work. You can get to it by clicking on my banner at the bottom of this post.
Anyway, I'll summarise some of the lesser known details about quality of life rather than detail the most obvious stuff.
Traffic has a huge effect on the quality of life. Traffic causes pollution so placing anything next to a busy road is going to suffer. Green roads are good for quality of life. Anything worse than that and the quality of life will suffer in proportion. A business next to an orange junction will generally have orange quality of life.
Holiday zones create huge bonuses to quality of life and are by far the best place for High Tech Industry. Stick your businesses into a holiday zone and this bonus can dramatically reduce all the other negative effects that I will discuss.
Industry itself reduces the quality of life due to Noise Pollution, so cramming 50 hi-tech buildings together in a block will reduce the quality of life. Not to mention having all that industry together is going to create dirty traffic as workers travel to those businesses and the big trucks shift the product in and out of the area.
Many of the leisure buildings reduce the quality of life. Yes, I said reduce. Most of the Sports Leisure industries create noise. Would you want to live or work next to a go-kart park or even a basketball court where there is lots of noise. There are a few quieter leisure assets but not many.
Schools reduce the quality of life. Yep, again a surprising one on first glance but again it's noise pollution. Loads of screaming kids.
Basically anything that creates noise is going to reduce the quality of life. It's not just the dirty heavy industry and manufacturing. Traffic is one of the worst though on any congested road. Stick an office near a congested junction and it will make less money than if you just moved it further down the road where the cars are not all clogged up.
Achieving a high (green) quality of life is difficult outside of a holiday zone but it is possible with clever planning. But watch out. You may place a hi-tech building in the perfect spot and find quality of life is green, but if you then get carried away and surround it with 20 more Hi-tech buildings it will ruin the quality of life. All the new traffic and noise from the buildings themselves will reduce the quality of life.
Avatar Parks (the 3000cr ones) are not cost efficient at all. I've tested them. There is no way to make the surrounding businesses, within the parks range, improve profits by even close to 3000cr. Landmarks can improve it significantly but again not cost effectively.
This simulation running the game is actually far more realistic than most people expect or are used to in games like this. Way more realistic than in the 2009 version. The amount of things that effect quality of life is very deep but it all makes sense. Hopefully some of the pointers I gave above will illustrate just how complex the simulation of the game can get.
If you want to know more and you are willing to sit back for a couple of hours and read through the many posts I've made in my journal you will pick up a ton of insight into how the game works behind the scenes along with lots more tips concerning quality of life.
Good luck guys and I hope this helped."