Parallel lines have so much in common. It's a shame they'll never meet.

Behind the Groan

Together but Never Touching

Parallel lines share the same direction and remain the same distance apart, giving them plenty “in common.” In ordinary conversation, people with much in common seem destined to meet, but geometry prevents these lines from intersecting. Deliver the first sentence warmly, like the beginning of a friendship story. Let the second sentence sound genuinely regretful so the mathematical rule becomes the sad twist.