Feeling cranky? Perhaps a constructive way to blow off steam is to read through the University of Oregon Medieval Studies Department's Medieval Insult Page.

The site includes a varied collection including the Old Norse:

"Thú ert brúr Svínfellsáss, em sagt er, hverja ir níunda nótt ok geri hann thik at konu!"
"You are the bride of the Svïnafell troll, as people say, and every ninth night he treats you like a woman!"
-- Skarpheinn to Flosi in Njal's Saga, ch. 123

Or from the 10th century German/Latin:

"Vnde ars in tine naso (canis culum in tuo naso)!"
A dog's butt in your face!
-- from the earliest Berlitz translation guide written for a Frenchman traveling in Germany, 10th century