This happens more often than I care to think about, but it is happening right now and I need to vent. I design book covers.
Client: Oh, I want to go with this design attached.
Me: That's a proof I sent last year, I will have to make it again, I no longer have that file (as it was one of about 20 you had me do, change redo...).
Client: Well, I just sent it to you.
Me: No, I can't use that one, it's very low resolution, not sized properly for the new trim size of the book and it's the wrong color gamut.
Client: Look, I attached the exact cover I want, use that.
...me, adding ice cube to my vodka. Ahhhhhh.