The trigger for me to bring this up again is an activity I came across at Dubai's Expo 2020 Sustainability Pavilion.
I've known friends in both situations, and they do it for years, and it gradually eats at them. I see them change.
Getting paid well and not learning much at work. When I was employed a while back before starting my business, I had one particular job where I wasn't paid as much as my friends but I was learning so much. My friends at the time felt bad for me as they were comfortable in their jobs, being paid well, not stressed, and have a day-to-day routine. Fast forward three years later, they lose their job and need to move somewhere else, they found it very difficult to find their next job because in three years while they were comfortable, the market had moved beyond them.
Getting paid well and unhappy: I see that in my friends who are unhappy and start to be bitter (either angry or sarcastic). Plus, they end up taking comfort in nicer cars, nicer houses, fancier parties, and nicer clothes. Nevertheless, their day-to-day is not something they enjoy. We all have bad days at work. I'm a business owner and there are some days where I don't feel like showing up to work. If your week, overall, the sum of the positive feeling is better than the total of the negative feelings, you are in a good place.