There are many jobs that will need to considerably change - and I think that's a good thing in the end. For example no more restaurant staff working for tips, at crazy hours, without proper days off. That's one I'm familiar with (in the UK though) - these people work in absurd conditions and are so used to it they don't even realise because there's 10 other people lining up to take their position. Your restaurant steak will get more expensive, and it really should.

If someone's doing an effectively-below-minimum-pay job at 30, I hope they just quit if universal basic income is introduced.