When Mercury is in retrograde, electronics and communications get messed up. The gremlins come out. Stuff gets fudged up is what I'm saying. It's like the full moon is to humans.
Here's my anecdotal proof:
My flyers for a show that is 4/20 were supposed to be delivered this 4/13 am (I paid for Rush and Next Day AM).
When they didn't show, I called my printer's customer service which is in CA. They tell me that the flyers won't be delivered until Tuesday because of some bottleneck that happened in the printing process in their plant in KY. And everyone there had gone home for the day but my super rush job was still drying, meaning they didn't print it until Friday. The original layouts are a 45 minute drive on my work machine. So I grabbed the artwork out of a PDF I emailed to a friend and made a 4up and took it to FedEx Office, 55 minutes before they closed.
It was empty and the sole employee knew who I was from my earlier frantic phone call, so he pulled the file right up and sent it to the printer on card stock for a proof.
The card stock wouldn't feed. He fiddled with the printer for a bit and then re-sent it. Card won't feed. He's adjusting all the settings. Going through all the menus. Fifteen minutes has gone by. There's a customer behind me but he hasn't spoken.
"Do you have like a 60# or 70# gloss paper instead?" I asked. I knew that the card stock's finish was going to be to rough for this design anyway.
"Well, I'd really like to figure out why this printer won't take the card stock. I have all the settings right," the employee replied.
"Ok, so change the paper to the gloss and forget the card."
"But it doesn't make sense. This should be working."
He shows me about 50 sheets of gloss stock and I tell him to run it. It's now 8:25pm. A large man who looks… odd… has entered the store and is walking around talking loudly on his phone. I've never seen a red yarmulke with black trim before. And it matches the tracksuit (black with red trim) really well. His outfit is really well coordinated except for an overcoat that came out of a trashcan and is held together by staples.
"Hm. This stock isn't going through either," said the employee. He fiddles with the machine. He adjusts something. "I just don't get it."
"Is the problem my PDF?" I knew it was a bit wonky the way I threw it together.
"No," he says, "It shows up fine on the screen. There's a problem with the printer. It's so weird." He goes back to looking at his various screens trying to get communication to work with both hands, like a 70s-era progressive rock keyboardist.
"This would be a great thing to figure out some other time when I'm not here. I just want some prints." I go and stand over to the side. The large man walks by me talking loudly into his phone and I wonder why he doesn't just stand in the back of the store if he's going to do that.
"Well, I think what I need to do is re-boot the system."
"Ok," I say.
Time passes. Spring becomes Summer. Summer becomes Fall. The beautiful girl becomes a crone before he replies. "It's 8:35pm and we close at 9. I'm not going to re-boot it now. It's going to take a long time. It's so weird all of the glitching I've had today."
"That's because Mercury is in Retrograde," I said and I left noticing the large man with the yarmulke did not actually have a phone.
tl:dr My advice is to allow for additional production time when Mercury is in retrograde.