It may be easier to talk about progressive taxes in the context of wages.
What percentage of a pay cut could you afford to take? What percentage would devastate you and leave you looking for a new place to live? How much would put you into dire straits?
For lots of people that number is pretty low. 5-10% cuts would devastate lots of working people. I'm doing pretty well so I actually think the number is closer to 40% for me.
Part of why we're mad at the rich is that the answer is over 100%. You could make it illegal for Jeff Bezos to ever collect an income ever again and it would never create any real insecurity in his life whatsoever.
We can come at it the positive way too. How much of a raise could change your life completely? Make it better and make your concerns go away? For lots of people this is also pretty low. A flat 100% might be more money than they ever expect to make in their entire lives. A 100% increase basically represents the maximum job growth opportunity in my field.
What did the mega-wealthy do? In the case of Jeff Bezos we can estimate it at 499900%.
For the truly, exorbitantly wealthy, any increase means nothing. There's very little they can't buy. If you gave Jeff Bezos another billion dollars is it even possible for his life to improve any more than it already has?
Handling these sorts of differences is roughly what the progressive income tax is about.
We come here in search of a place to express our thoughts outside of the direct control and surveillance of unaccountable, mega-corporations. There is no common theme that binds us other than these being the bonds we've chosen rather than those that have been chosen for us.