The answer is easy - just honestly quit. You don't have to justify or search for some reason to get fired.

Go on a chainsaw-rampage?

Nothing says "I want to get fired" more than a nice mornig coffee, getting the sweet smell of gazoline into my nose, hearing the satisfactory sound of my little baby machine and then going all psycho! Mask is optional :)

If male, slap him in the face. This will surely get you fired, unless he has a crush on you!

If female, tell her you will slap, and this will get you fired + some jail time if she decides to file harassment case!

Find another job

depends on the law of the country and the contract i guess. In europe there are a lot of worker rights, because of the socialist movements of 1840 - 1950 and the wars .... other countries like america have less rights for workers.