A Thin Line Between Genius and Insanity

At work a woman was eating a huge apple. Perhaps the biggest apple I've ever seen.
I said to her "it's a good thing that apple didn't fall on Isaac Newton's head. He wouldn't have been inspired to discover gravity. He would have gotten a concussion and probably died."

After laughing, another co-worker who overheard remarked on what a strange comment it was to make. He said it was funny but seem gobsmacked that my mind worked in such a way that something like that would come out based only on the stimulus of seeing a large apple.
Please vote whether the comment was funny or douchey, but also let me know in the comments if you think that comment is more indicative of genius, or of insanity.