A while back one of my clients requested all their computers update automatically on schedule, not a problem. Also they are very specific and set-in-stone about the process, kinda annoying but still not a problem........ Until this conversation happened (also im paraphrasing).
Client: "So this needs to happen on Wednesday night" (What im not telling you is the 10 emails a day im getting about the importance of it being on Wednesday.)
Me: "Ok, how about 9pm?"
Client: "Errr... some people work that late. Can you push it later?"
Me: "What about 11pm then?"
Client: "hmm.... its a bit later but can it be later?"
Client: "Later? Some people remote in late when there on vacation"
Me (internally): "Actually no, 11:30 is physically the latest time possible for Wednesday. Because 12am is Thursday" (system likes 30min marks)
Me (externally): "We can make it early Thursday mor--"
Me: "You want it 2am..... on Wednesday?"
Me: "ok, 2am Wednesday morning. On Wednesday"
Client: "Yes! Thank you"
---I do the thing and on Wednesday at about 10am this happens ---
Client: "Nagol93!!! Why did the computers update last night!?!?!? I thought we agreed on 2am!!!!"
Me: "We did agree on 2am WEDNESDAY, and I set it for 2am WEDNESDAY, and it happened at 2am WEDNESDAY. Its now 10am, 2am was this morning."
Client: "NOOOO! Wednesday night ends when we come into work on Thursday. NOW FIX THE THINGS!!"
Me (internally): "My god, this person actually dosnt know how to tell time.........."
Me (externally): "......... ok"
Fast forward a few months, to this vary day. The updates happen on Thursday at 2am, but you have to call it "2am Wednesday" or else the client gets mad and starts yelling. All attempts to explain to them that they actually mean "2am Thursday" have been unsuccessful.