My oldest son, Colin, is ADHD and Autistic (“on the spectrum” as they say). Although I hate using those terms to “define” him. He is so much more than those terms.
He is a very challenging, and very special, little boy. My wife and I are very lucky, as far as parents of children on the autisim spectrum go. Colin is VERY verbal. That’s not to say he communicates easily, but he basically talks nonstop. He is not really able to have what one would call a “normal” conversation. Colin’s coversation skills basically equate to constant questions. Even questions he knows the answers to. ESPECIALLY questions he knows the answers to, actually. Plus, like a lot of other autistic children, Colin repeats words and phases he has heard from other people. Whether he knows what they mean (or even if YOU know what the mean) or not. This is called echolalia.
So, I don’t know exactly where the phrase “good day pickle” came from, but I can give it an educated guess. I’m pretty sure it started with one of his teachers telling Colin, “You’re a pickle”. Since Colin doesn’t really understand something like that, he thought it was hilarious that someone thought he was a pickle. He started calling people that all the time. Even upon first meeting someone, he would say, “Hi! I’m Colin. You’re a pickle!” The fact that this would usually elicit laughter (even nervous laughter from strangers) just encouraged it.
When Colin would go off to school every morning, I would call after him, “Have a good day!” He managed to turn that into “You’re a good day pickle, daddy”.
When I started dating Sara (who would become my wife about 8 months after we met), she thought it was pretty funny, too, so it soon became a catch phrase between the two of us as a way to kind of put a smile on each other’s face whenever Colin was being “difficult”.