I've done this a number of times -- leaving a job in order to take a lower-paying job somewhere else. Almost every time, it's been because the "somewhere else" was doing something I specifically had a great interest in, or that involved a skill I wanted to learn.

However, I have engineered my living situation in order to make doing that pain-free and easy. The main rule is: don't get used to having a high income. If you actually incorporate a high income into your life, then taking a lower wage can be very painful. If you avoid that, it's pain-free.

So what I have done is to determine what the lowest amount of income I can really take without it bothering me, then live on that amount of money. Extra pay above and beyond that gets invested/saved/etc. and I pretend that it simply doesn't exist.

Doing this gives me a large amount of mobility and freedom to choose great jobs that may not pay as much as others.