What does "bite the bullet" mean — and why is it funny?

informal

Meaning

To force yourself to do something difficult or unpleasant that you have been avoiding.

Where it comes from

Often traced to battlefield surgery before anesthetic, when a patient was given a bullet to bite down on to endure the pain.

Why it is funny

The humor is darkly practical. The image is grim, but the phrase uses it lightly for ordinary chores — paying a bill, making an awkward call. Comparing your dentist appointment to enduring surgery without anesthetic is an overstatement so theatrical it becomes funny.

Used in a sentence

"I hate paperwork, but I'll bite the bullet and finish my taxes tonight."