An archaic, windows-only Java app to generate pairs of password-protected keys, which then have to be fed back into the system to declare your tax status. And they expire every so often, so you have to track down your old keys from years ago and remember the password. Confused? Just set up a SAT appointment, they'll be with you in... weeks.
Having to declare your tax categorization multiple times per year.
Facturas that companies will only generate for you for a limited amount of time, and complicated questionnaires to fill out if you DO want one so you get the right type. Assuming they'll even give you a factura at all.
I fully admit that I have an incomplete understanding of the system, this is just what I've seen my wife try to deal with. And she's the equivalent of a 1099 so her situation may be more complicated.
1. All my incomes are automatically filed. 2. Each month I say "yes this is correct" on the website, and pay immediately via any bank. 3. At the end of the tax year, the system calculates if they own me money automatically, I give it my bank account and in some days I have my return.
It even handles tax deductibles and everything.