It's not that you shouldn't work at a startup, it's that you shouldn't let the startup convince you that their stock is going to inevitably be worth millions so

It's not that you shouldn't work at a startup, it's that you shouldn't let the startup convince you that their stock is going to inevitably be worth millions so you should accept a tiny salary up front. Don't be Jack from Jack and the Beanstalk -- don't trade your cow for magic beans if you need to eat. Only make the trade if you won't be worse off if those beans don't turn out to be magic.