I bought the business I had been working at for a year which had been going about 10 years and was run by an elder and his wife.
When I went to submit my quarterly tax returns I discovered the business had never paid tax before as it was being run illegally and without the correct paperwork.
I went to another elder with "my problem" and was told "It's very difficult to run a business legally in Spain"
One of many aha moments prior to my exit.