BUT: Sometimes the current job is just the current job, so don't over-react, either. I've seen 3 people have a bad time from either overwork (dotcom era) or bad roles (at a good company) and change careers very dramatically. One opened a record store in Seattle, and 2 became chefs. I'm not saying they were bad decisions, except maybe the record store; but sometimes you need to try out another company first.
Or, you need to try out the job you think you want, and see if it's really better. That's the service provided by this interesting company, Vocation Vacation. That bookmark goes to the photographers' page, which I occasionally stare at.
The idea is that you go on a vacation where you work with someone in the career who acts as a mentor and shows you the ropes. It's like an internship, only shorter, and probably for older folks like me. If you saw the movie "In Her Shoes," there's a great career switch in there, from high-powered stressed lawyer to something much more fun, along these lines:
Dog Day Care Owner.Do you sit in your office and wonder what Rover is doing at home? If you dream of your life going to the dogs, then this VocationVacations® holiday is for you! Dog Daycare owner Heather Stass would love to share her passion as Top Dog at K9 Capers Doggy Daycare.
Heather has extensive experience working with animals. She has a Bachelor’s degree in animal behavior and multiple years of kennel management experience. As a Dog Daycare owner she belongs to the North American Dog Daycare Association and the American Kennel Association’s Dog Daycare Division. She has owned K9 Capers for four years. more...
Before you completely ditch your job and current career, try out a new one and see if it's really that much more fun. Or, in another bold move, do two at once for a while. That's how one of my friends did it -- she sleep walked through her old bad job (remember, virtually no one gets fired for not doing much) and started up her new career after hours and on weekends, till she was ready to quit the first one.
If you're self-employed, having two jobs at once, either two clients, or two different professions, is another way to stay energized. You always have a backup and an escape from what you have to do Right Now.
Finally, if you're thinking about changing jobs, here's another kick-in-the-pants if you still need it: The Right Career is Yours for the Taking.