Shorter Than a Thumbtack

Alright, listen up, buttercup. This joke is all about being short. Like, REALLY short. The joke compares the person to a thumbtack, which is tiny. And then it says their aunt is probably taller than them, which is just adding insult to injury. It's funny because being short is often seen as a negative thing, and this joke exaggerates it to the extreme. Also, I bet you are short too.