Y'ever had this conversation:
Him: "Hey buddy, can you do five things for me?"
Me: "Sure, can you do one for me?"
Him: "Of course!"
...time passes.
Me: "Hey, I've done four of those things you wanted. How's mine coming?"
Him: "Oh, I haven't even started it yet."
Me: "When are you going to start?"
Him: "Soon! I promise!"
...more time passes.
Me: "Well, I'm almost done with the fifth thing... how's that--"
Him: "Will you leave me alone about it?! If you keep bugging me, I'm not going to do it!"
...more time passes.
Me: "Well, I've got your fifth thing. I see you've been using the first four a lot lately..."
Him: "Look, I'm not going to be able to get to your thing right now. Can you be a little more patient with me, after you give me #5?"
Me: "Not really... I've done what you asked and waited a long time for your end of things."
Him: "Yeah, whatever. You're just unreliable, you know that?!"