I had a "good" job at one point. I didn't put money into a 401k because I knew I wouldn't be employed there forever.

Let's say you're 25 and you put 6% of $50k/yr into a 401k and then get fired 4 years later but then the best job you can find afterwards pays only a bit more than half of what you were making. You don't get that back that until you're 65 or whatever. That would have been $12k that's just gone. I want to actually live to be 65. I needed that money. I'm glad I didn't do that.

I might not have a retirement but at least I've (so far) never been homeless or had to live in my car.