Just read in the Wikipedia Article on Insult that you could be punished for up to one year in prison for insulting someone in Germany. What kinds of insults, assuming that they are free of false accusations or any accusations, can get you in jail in Germany? Would making fun of the way a politician looks, done routinely in the US, for example, fall under this category, assuming that the politician presses charges? Calling someone a bad word?
Here are a few examples (sorry, they are in German)
So it does actually happen, but it's fairly rare. It typically involves abusive behavior: frequently repeated insults, defamation, and threats and also ignoring any cease and desist orders or requests to stop the behavior. There is also a pre-existing criminal record: it's not the first time they stand in front of a judge for this type of thing. The guy in the last article had already 12 previous offenses so the judges felt that a fine or probation is just not working.
So it's not so much the exact type of insult but more about relentlessly barraging the victim and having an existing pattern of bad behavior and related offenses.