Follow the money and second and third order consequences rather than simply trusting the claims. Where does the money come from? What happens when the source of that money disappears?

There's a well known saying in economics: tax what you want less of, subsidise what you want more of. I think that saying has merit and one doesn't need to look very hard to find evidence to support it. Suppose we apply it to UBI? Could it not be said that we'd be taxing wealth/success/innovation and subsidising idleness? If the saying does indeed have merit, what do you suppose the downstream consequences would be?

So far, you seem to be focusing on the "gimme free stuff" aspect of UBI, not who pays for it. Millionaires and billionaires only have a limited amount of money we can steal. Once it's gone - it's gone. Then where does the funding for the next year come from? The next Bezos won't fail to notice this and might (understandably) decide the juice ain't worth the squeeze. Or more cynically, none of this will affect the billionaire class as they will structure and/or relocate their assets to mitigate the losses.

UBI only works by taking $3000 from you and giving $1000 back to you, and $1000 each to your two unemployed neighbors until you decide to quit and just rely on UBI from the guy across the street, until he quits...