How do you tell someone you've broken their blender jug without them going mental and kicking the crap outa ya?

Hmm, you might can buy them a new blender jug before they figure out that it's missing and broken, considering that he might lose his temper if you tell him my best advice to you is buy another one before he realizes, because he'll get even more mad if you don't tell him. If you are going to tell him, be like, 20 feet away from him and tell him how you accidentally broke it. But try to see if you can buy another blender jug first...