Let's call them Allen and Betty.
Allen and Betty are in the supermarket. At the register, Betty tells Allen "I couldn't find the walnuts." Allen says "hold on. I'll go and check for them."
Allen goes to look for the walnuts. After 5 minutes he returns because he sees Betty motioning that she has been checked out already. When Allen meets Betty, she immediately says "You're ridiculous. I held up the whole line because of you. It was insensitive to the other people in line."
Allen: What are you talking about? Why would you do that?
Betty: Because you didn't come back. I assumed you were getting them.
Allen: What? I was trying to get them.
Betty: Okay, calm down. This was a miscommunication on both of our parts. I assumed you would come back and tell me the status, so I held up the line, waiting for you to come back.
Allen: No. I figured you would check out normally. If I happened to have found the walnuts while you were still in line, we would get them, and if I didn't come back in time (or came back empty-handed), then we wouldn't.
Betty: I assumed you would come back to tell me the status. Besides. Didn't you realize that 5 minutes had passed? How long do you think it would take to check me out?!
Allen: I figured you were probably done. I tried to tell the staff to stop looking, but they kept talking to me and I felt bad telling them to shut up because it was futile at that point. Anyway, your assumptions make no sense. Why would I come back to tell you the status? That just wastes time and confuses the staff who is trying to find me.
Betty: Umm no. You say to people "Bye. I have to go."
Allen: I was trying to. Anyway, you're failing to think about each of the possibilities: 1. the walnuts were there (in which case I would have just come back with the bag), 2. they weren't there (in which case I could be in the process of asking the staff if they could locate them in the back for me, which is exactly what happened). It's not just "there" or "not there." It's more like "there" or "possibly there," which is why my "if I happen to come back with them in time" makes the most obvious sense.
Betty: Not obvious. The cashiers were waiting for you as well. Everyone thought you would come back with an update.
Allen: So now we're going by assumptions of the general populus? Geez. Sorry, I don't do THAT.
Allen: You know I'm only half serious.
Betty: Why are you getting so enraged over this?
Allen: You called me "ridiculous." It's fine when it's about stuff that is ACTUALLY true, but I make perfect sense here and you're the one with the absurd system.
Betty: Whatever. I don't know why this bothers you that much.
blah blah. Allen and Betty hug and make up.