Email from Client:
Hi, we'd like this and that done to our website. I know you aren't finished building it yet but I believe we can change what we agreed upon.

Me:
Let me see what I can do, I'll try squeeze in some of those changes but the bigger ones I'll have to check with the boss.

Boss:
Yes, we can do those changes at an additional cost, quote them $1000 (example)

Me to client:
Hi there, yes we can do that but we have to charge $1000 for those additional changes that weren't initially agreed upon, and we'll need an extra week on the deadline.

Client:
Oh no no no... I know how this works. If I wanted to do this myself I would. You will do the work and get it finished in time, and I will only pay you $200 for it. I don't like being scolded for money.

Me and Boss: Yeah.... this isn't working out. Please find a new company to deal with.

Conclusion, this client was always giving us problems and telling us how we should be charging and how we should be doing our jobs. It was so satisfying to just them let go.