I grew up poor or lower middle class. But later my parents' finances improved and my siblings grew up upper middle class.

I can tell you there is huge difference between my siblings especially youngest and I when it comes to finance and career.

1. They barely save any money, live pretty lavish lifestyle for what they earn. I pretty much focus on saving. Sometimes, I will skip important events, dinners, etc because I haven't met my savings goal. Before I got married, I lived in 33% of after tax income.

(My friends split in two groups after college, those who upgraded their lifestyle as they earned more money, and those who either kept college lifestyle as long as possible or did not earn a lot after college to upgrade their life style. I remained friend with later group only.)

2. My siblings don't take shit form their bosses, quit jobs without finding next one. I worry too much about my job, answer phone or emails after work etc.

3. My siblings will quit jobs and travel or find themselves or whatever. I have never ever voluntarily quit job without finding next job.

4. My siblings will risk significant amount of their savings in various ventures. I only invest in index funds.

5. They buy stuff on impulse. I will research best deals.

I can go on and on about difference in our mentality but main point is that somehow even with 6 figure income, I fear poverty more than I should. And they pretty much live as if money is unlimited resource.

This also causes issues with my wife though she lived in poverty a bit too, so she understands my fears.