My girlfriend said she was pregnant, and I was so happy that I went out overnight to buy a ring and propose.

She took the ring, smiled, and said, "Just kidding, I'm not pregnant."
I was stunned: "Why did you lie to me?"
She said, "Because if I didn't lie to you, you would never take the initiative to propose."
I sighed in relief: "Then the ring..."
She put it on and said, "Of course I won't return it. Next time you're really pregnant, buy an even more expensive one."