Worked for a friend of mine in the early 2000s. Had to implement a booking system into PHP for some private customer. This was PHP 4.something, the CMS was some alpha release of an open source project that my friend was sure was the future (it wasn't), and the specs were one A4 page of pencil scribbles that he took while talking to the customer.
Deadline was insane, nothing worked. I worked from getting up to laying down to get shit done, not being able to sleep, feeling stressed all the time. One week before roll-out I actually managed to get it running and we showed it to the customer. He was like "nope, that's not what I meant" and demanded lots of changes but accepted only one or two weeks of roll-out delay.
I did finish the job, made some good money, but then quit as soon as it was done.
This experience broke me so much that I worked in a workshop for 2 years to get away from programming as far as I possibly could.