There are times when we decide for ourselves that crunch is a good idea. When we do that, we crunch for peace of mind.
To be clear, it is peace of mind for an extremely tiny portion of the brain. Chances are the rest of the mind is screaming.
The main purpose of crunch is to convince yourself that you did your best. Your health, relationships, and sanity in every other aspect of your life could be collapsing. But at least your brain knows it couldn’t possibly be working any harder.
This explains the paradox at the root of self-imposed crunch: why do people still do it when over long periods of time you don’t actually get more done? Because people desire the feeling that they couldn’t possibly have gotten more done than the reality that they did.
Feelings are concrete. Progress is relative.
The same incentive applies to other feedback loops like dieting. It’s easier to attempt dieting by eating far too little food for a short period of time than it is to change your diet to become healthier. Hunger is a crystal-clear feedback signal that tells you at least something is happening! You don’t expose yourself up to ambiguous questions like “what is healthy?” and “how many calories provide me with a healthy rate of weight loss?”
These same types of ambiguous questions are side-stepped by crunch. Questions like “what is my long term goal?” and “what is a sustainable rate of work that will enable long-term progress towards that goal?” It is comforting and easier to quiet these questions by working to the point where they seem vain to even consider.
In the end, people will always prefer a short feedback loop they can feel over a long feedback loop with short term uncertainty. But in the end, getting a long term strategy half-right is better than papering over the anxiety of uncertainty with emotional brute force.