I recently said that I was too tired to continue during a project planning meeting stating that my input at this point would be flawed. It was a pretty informal meeting but I had been working 12 hours solid* without a break except the necessary and to the drinks vending machine a couple of times. The same was true for another couple of guys there. The response I got from the most senior team member was "OK" then he carried on regardless. "Brilliant" I sarcastically thought. We then produced a whole set of estimates which were later found to be underestimating the effort required. The most senior team member has now had to take indefinite leave due to stress and the project has now been canceled.

I'll leave it to my fellow forum members to draw their own conclusions.

* I used to be able to do more without breaking into a sweat but ho-hum.