One think I learned from these type of situations is that it is important with some clients to stretch how difficult the project is and keep a constant flow of signals that show the hard work we put into the projects. In my perspective everything is super difficult. Unless the client knows that it is super difficult then it must look really easy. But it is a very nuanced approach, not that black and white as I describe it.
The client must take away the feeling of "they moved heaven and earth for me and I really can't expect them to pull such inhumane hours for me next time" and not "well, they clearly can do a lot more if I just challenge them a bit more". It depends a lot on the client relationship and the related communication.
I recently had a waitress who "moved heaven and earth for me" (that's the phrase she used over and over and over again and again and again). I don't doubt that she got the cook to do a favor for me, but hitting me over the head with it until she was blue in the face actually made me lower my tip.
As in all things, there's a balance - having the client understand that it wasn't a cake walk is important, but not beating them over the head with it is important too.
The client must take away the feeling of "they moved heaven and earth for me and I really can't expect them to pull such inhumane hours for me next time" and not "well, they clearly can do a lot more if I just challenge them a bit more". It depends a lot on the client relationship and the related communication.