(Mis)management and crises
As I too rapidly approach 25 years as a working engineer, I have found this to be invariant: If a company mismanages itself into one crisis, there will always be another. Management that repeatedly over-extends their development capabilities and habitually over-works their "exempt employees"(*) always encounters another "emergency", often before the current crisis ends. They consider this to be a sign of management prowess, rather than proof of ineptitude!
Experience shows that true emergencies are few and far between. Most problems were seen coming far in advance, but were swept under the rug to save money (or to avoid admitting schedule trouble). The cost and time to fix the festering problem mushrooms, causing new "emergencies" to erupt as resources are "temporarily" diverted to the crisis du jour. Exponential growth at its worst!
If you're working more than 10 hours in any day or more than five days a week, you're likely to be losing more time correcting mistakes than you gain in extra productivity. Mental and physical fatigue will do you in--not the first day, maybe not even in a month--but sooner or later overwork will eat you alive. It's not worth ruining your health and your family to slave over a product that nobody will care about ten years from now.
Your best bet is to do the best work you can, while keeping your eyes open for a (less in)sane employer. When the right opportunity comes, bail out (and don't feel guilty about it--guilt is the abuser's favorite tactic, both in the workplace and in personal life).
(*) For non-US readers, an "exempt" employee is one who is not legally entitled to additional pay for overtime work. Unethical employers commonly abuse this by assigning far more work than can be accomplished in the presumed 40 hour workweek. The really daft ones waste the entire 40 hours on useless meetings and other counter-productive nonsense, so that all the productive work must be done "off the clock"!
Wow. tcgroat hits it dead-center.