Tax evasion is Portugal's national sport

I have noticed so many examples of tax evasion, both by businesses and Portuguese citizens.

People on sick leave for years receiving subsidies while working off the record so not paying any taxes.
Businesses regularly asking you if you want a discount to pay in cash and not emit an invoice. Or saying that they don’t accept credit cards until you say you need an invoice for company reimbursements.
Accountants helping small businesses to cheat the system.

It’s all over the place, from individuals to politicians.