I've just come across a German law which says that if you insult someone and they report you you'll be prosecuted. Punishment is up to one year in prison, or up to two years if you insulted the person in public or in a group setting. Or a fine.
In case people think that this only applies to really serious insults, here's some advice from a German law firm:
Examples of criminal insults:
VERBAL INSULTS:
Calling someone an ‘arsehole’, ‘idiot’, ‘slut’ or ‘scumbag’.
A member of the public calls a police officer on duty a ‘cop scum’.
An employee calls their line manager a ‘loser’ during a meeting.
GESTURES AND ACTIONS:
Giving the middle finger whilst driving.
Making an obscene gesture during an altercation.
Spitting at someone’s feet.
INSULTS ONLINE:
Defamatory comments on Facebook, Instagram or Twitter.
Sharing defamatory memes or caricatures.
Insults in WhatsApp groups.