You have to avoid these bad habits because they become vicious cycles that are difficult to break. Consider Dan's point on heroics:
"Some managers encourage heroic behavior when they focus too strongly on can-do attitudes. By elevating can-do attitudes above accurate and sometimes gloomy status reporting, such project managers undercut their ability to take corrective action. They don’t even know they need to take corrective action until the damage is done. As Tom DeMarco says, can-do attitudes escalate minor setbacks into true disasters."My biggest issue with this is that you've hidden the true cost of a piece of work from the business. How can you possibly make valid, prudent decisions that are in the best interests of the business if you don't have a true picture of what things cost? Cost is one of the most basic, and critical, inputs to how a business is run. Even though these heroics are often embarked upon with the best of intentions, hiding the actual cost of a feature actually does the business a huge disservice.
Once you're in this pattern, how to you reset expectations? There is no point at all in talking about the triangle and other real life constraints if you artificially modify the values though this kind of behavior. You also lose credibility with the rest of the organization - because working this way is unsustainable you'll eventually find yourself trying to get things back on the rails, at which point you'll be met with doubt; and fair enough too - you've been doing it so far, right?
It is hard to break out of these cycles and get your team back to a better work/life balance and so, much like smoking, my advice is the best way to quit is not to start in the first place!