Bad choices or different ones?
That's the attitude that I disagree with, I'm actually not that unhappy with my life as it stands, I have made different choices, I'm where I am, and I don't resent that, what I resent is the notion I made bad choices because I haven't achieved what you have. (Broadly speaking).
I have however worked hard to overcome different challenges to yours and do consider that I have achieved more than I would have had I not done that. But because I'm not where you are doesn't mean I have automatically made bad choices. There are very likely completely different circumstances and challenges at play for both of us. That doesn't mean I haven't worked just as hard as you, or you haven't worked just as hard as me.
I often think the reason that people respond with comments about luck, privilege etc is in response to the attitude that if you haven't achieved what someone else has it's because you've done something wrong. That financial achievement is the only yardstick by which to measure the whole person.
I may well have contributed far more towards society with the jobs I have done than you have (I'm not saying that's an absolute, just a possibility) but because I haven't earned as much (and by extension I find the implication of not having paid as much tax) then I am somehow lacking as a person.
I don't resent your earnings, success or status, I do resent the implication that I've made bad choices that have led me to somehow be 'lesser' - especially as for much of my working life I have done jobs that benefit people (and made people a lot of money) and it's not valued.