Farming Simulator is by far my favourite franchise!
The reasons are:
1- Its absolutly relaxing gameplay, the closest you can get to nature without leaving the house.
2- It is by far the most deep game that can still be played "passivly", meaning you can fullfil other life duties such as reading/ studying and still enjoy this game in the background.
3- Has enough activities to engage you when you have more time and choose to play more "activly".
4- Even provides multiplayer to enjoy with friends!
5- Very educational for urban people like me who never even knew a thing or 2 about farming.
I will gladly recommend all the versions even today: 2011, 2013, 2015 every game has a set of achievments and the older it is the more basic the gameplay is. So if you are new to the franchise you can happily start from the oldest one but if you are looking for eye candy of course the newer look better ;)