Heroic Developer

Look, over in the cube. It's a nerd. No, it's a geek. NO! It's Heroic Coder. Coding longer than a puny developer! Introducing bugs and errors faster than a marketing drone can dream up the next greatest feature. HEROIC CODER!

Seriously, how long can we take it? If the manager can't plan the project based on sustainable and healthy working hours over time, then you need to push back. Just because you can work late into the wee hours of the morning and over the weekend doesn't mean you should. Take a break, go home and drink a cup of tea. Go for a walk and read a (non-technical) book. Your brain needs a break. Spending too much time trying to hack in another knee-jerk requirement is going to end up taking longer and wear you out, leading to increased mistakes and a myopic view of the problem. That tunnel-vision and fatigue will only add up to having to spend more time later debugging a rapidly deteriorating code-base while still trying to shoehorn in yet another new feature. It's a vicious cycle and it's up to you to break out of it and take on the mantel of "Professional Developer".

Heroics == Hours Spent
Professionalism == Effort Maximized