If you have a full-time job then it's likely you spend more time at work with your colleagues than at home with family and friends.
As such, it can make a real difference to your performance if you have a role you enjoy and co-workers you get on with, given you'll be working in such close quarters.
Unfortunately, this isn't the case for everyone and some people may find that their job, or more specifically their boss, is actually making them unwell.
