I can't really agree with JoshuaH's argument at all, it comes from a position of privilege. Only someone who has food and housing security would even argue that more adversity is good for you. By that logic, homeless people should be the happiest, and those who inherit great wealth should be miserable. We don't see that however.
You also have to note that UBI generally could replace progressive taxation. The argument against UBI should also be an argument against tax credits for low-wage workers, since they're economically indistinguishable.
e.g. it would be a better system if every adult got a lump-sum and you pay the same income tax (say 30%) on every dollar earned. Then, it replaces:
- welfare system
- progressive taxation
- tax returns
- food stamps
etc etc, while also removing the "penalty" for working part-time where they cut you off welfare. More people will choose to work moderate amounts, because currently, "moderate amounts" of work is artificially penalized because you lose more welfare benefits than you gain in income, so most people are basically forced to work either 40 hours or nothing, and no in-between unless you have some other source of income, such as a full-time employed spouse. UBI will open up part-time work to more people, and with higher numbers of people choosing lower numbers of hours, then that will in effect offset declining employment levels (more people working less hours each).
There's also the fact that if you're getting UBI, you aren't as beholden to your boss, so you can tell them to shove it if they suck, without risking homelessness. That increases the bargaining power for wage workers, meaning bosses will need to treat you better. Plus, since "money" won't be the sole driving factor any more, the bosses will have to shift emphasis to non-monetary rewards ... e.g. making jobs that are pleasant and meaningful.
There's also the fact that if people in general have more leisure time then that's going to be a big boost to the consumption of media, and someone needs to make all that media, which means more jobs in creative fields.