Some people see sick leave as extra holiday entitlement, others as just an excuse not to go to work. It's easy to criticise though, there must be loads of people who have poorly paid incredibly mundane jobs who are treated badly by their equally poorly paid or bored bosses whose only joy in life is the fact they are one rung above and can treat their subordinates with distain.All too often any attempt to make work more enjoyable isn't even thought of.
That said I was lucky to have an interesting job, was well paid for what I did and as a consequence spent 30 years with my last employer and had no more than a handful of days off for genuine sick leave. A younger colleague who had only been in the job a couple of years, well perhaps five, took a year off with stress whilst setting up a new private business. Within a week or two of coming back to work they resigned.
Different age, different attitudes.
The more that's given, the more it's taken.