I had various points in my career where I turned down a short term gain of 5 figures and even possibly low six figures because in the long run I thought it was best for my career development and financial situation down-the-road. At that point in my life, I was certainly "well off" by most standards but far, far from rich (and no, I don't come from money either).
I liked my present circumstances, and thought it was a better move for my future financial earnings and career development to stay at my current employer, betting it would position me to make more money down the line.
And it did.
Not everyone thinks this way, but I think there are folks who look at potential career earnings that come with development and being in the right situation rather than simply grabbing the most $ in front of you, especially when you account for taxes and such.
I don't come from a background where my family was struggling, so there's that.