What's your favourite paradox?

[aviator]

Did this recently as an addition to one of the topics I'm studying:
If 0.999... = x
9.999... = 10x
10x - x would give (9.999... - 0.999...) 9.
9x = 9 so x = 1.

Exactly, it seems quite unintuitive but definitely true.

God is not almighty.
God cannot create a stone, so heavy, he cannot life it himself.

A. If he could create such a stone, he could not lift it, losing his almightyness
B. He cannot create such a stone, losing his almightyness

100% true

Indeed, the omnipotence paradox, one of the many arguments against the existence of God.