Ho zero idea. ho 11 anni e mia madre mi urla contro senza motivo quando non faccio assolutamente nulla di sbagliato, nulla!

You said it yourself, „when we do nothing“.

Of course I can only assume, and I think this „nothing“ is literally something you did not do, like…

• did not clean the table before leaving kitchen,
• did not hang the hand towel correctly like she already told you 60 times,
• Put the wet plates in kitchen cupboard instead of drying them before,
• During dinner you and your brother make grimaces together, but for parents not especially funny,
• You did not finish your plate,
• In the angle of her eyes she sees your school backpack AGAIN put in the place she told you already 130 times not to put,
• Etc…

Bottom line is, that from her grown up perspective you did something (or did not do), what drives her crazy!