Modulus

Division was hard enough. Now you want me to divide, throw away the answer, and just keep the leftovers? Modulus is the dumpster diving of arithmetic.

"It's like a clock!" they say. No, a clock is a clock. Numbers are supposed to go up, not wrap around in a circle like a confused dog chasing its tail. 12 + 1 = 1? Get out of here.

And don't get me started on the symbol. %. It looks like a fraction that fell over. It's confusing, it's messy, and it makes simple addition stressful.