But if he did that he would be letting you down

Thereby creating the Astley Paradox

Yes

If you ask for it, he can’t give it to you, since he’s never going to give you up. However, he has to, since he will never let you down. He can’t run away either, since he claims that he’ll never desert you. He also can’t just kill you so he doesn’t have to, since he says he will never hurt you.

He can’t make an insult and get away with it either, making you cry. Something he also claims he would never do. He can’t just tell use goodbye and leave because he also said he would never say goodbye.

Never Gonna Give You One