I built a Drip emailer for a client. I delivered it and he demanded a bunch of changes – which was weird because they were actually all in the version I delivered. I tried telling him this but he insisted on version 2.

Me: Here’s the second version.

Client: Not bad, but it’s missing this feature.

Me: That feature was on the first version, and I confirmed with you that you wanted it removed.

Client: I didn’t agree to that!

Me: …

Seeing the writing on the wall, I asked for full payment before making final changes. 

Client: What? Are you some kind of scammer? I will call the cops if you try to rip me off. 

After a whole lot of arguing, he wound up paying me half of my fee and I delivered the second version with minor revisions. The frustrating thing is that the first version was actually what he wanted. Basically I did twice as much work to make half as much because he couldn’t be bothered to test.