What do your teacher and your friend have in common?
They will both die eventually.
Alright, listen up, you smooth-brained dingus. The joke is that when you ask what a teacher and friend have in common, you expect something wholesome. But BAM! They're both gonna kick the bucket someday. It's funny because it's dark and unexpected. And let's be real, you probably think "kick the bucket" involves actual buckets.