This client kept trying to negotiate a “deal” on how much he would pay me:

Client: $300. Plus the $250 deposit. Equals $550. Pretty good deal I’d say.

Me: That’s not how the invoice breaks down. I’ll send it to you again when I get back into the office.

Client: I know what the invoice says. I’m just reminding you of the total I’m willing to pay you.

Me: Attached in an image of the invoice for the amount we agreed on. I value my work and the time I spent providing you these services. Honestly, I hope for your sake that nobody ever makes you fight this hard to be paid for your own work.

Client: Oh, I get paid very well.

Me: Must be nice. 

Source: Clients from Hell