Funny,
I just worked an 18 hour day and I am not happy...
with the results or the lack of sleep. And it will take me a day too recuperate.
And it's all because they slave drove me into mixing too many songs in to short a time...
I don't mind working a little extra hard for a first time client, but otoh, I also don't want to set the wrong professional "tone" (read- I will work like a dog for you just because that's the kinda sucker I am)
I'm in the process of restructuring my rates as I rejuvenate!