Never-beginning... It makes my brain do back flips.
Never-ending I can get, you know, existence's end will never come, sure. It just keeps going and going. But, existence never began? Or if it did begin, what was before it? Some kind of existence had to have been... otherwise... how? There never was a beginning, and existence always just was and is. ARGH! The never-beginning is something totally weird and inexplicable that I pondered about from a very young age.