Imagine a pizza parlor with an infinite number of slices, each with an infinite number of toppings. Sounds like a mathematical nightmare, right? That's what sets are like, folks. Endless, unending, and utterly bewildering.
There are three axioms that rule the land of sets: the Axiom of Extension, the Axiom of Separation, and the Axiom of Replacement. Don't worry, they're not as boring as they sound. Unless you're a mathematician. In which case, they're the bane of your existence.
Infinite sums are the ultimate party crashers. They just won't leave. You add 1, then 1, then 1, and... well, you get the idea. It's like trying to get the last slice of pizza, only to find there are infinite slices.