Schrank, (edited ) 
How to design an asshole 🖕🖕invoice I process:
- Don't attach the I pdf to an email but add a link or worse: a note, to download it
- don't give the file a proper UNIQUE name, so I have to change EACH file before save (Bonus-points to use a term like "invoice")
- force me to login instead of using a magic link
- limit the shown I to the last 4, 6, 12 months
- don't generate a PDF in the first place, but a shitty email or HTML page
- Answer emails of I copies with a link to a FUCKING chat bot🖕