This saying is great literally and will spare you choking down a bad wine choice but it is also a great saying metaphorically. Life is short. It may not seem that way when you are a teenager or in your twenties but as you age, it becomes very clear. And with such a short time, you should not waste any time doing things that make you sad, unhappy, or bored. Do things that you enjoy, that make you happy, or bring you fulfillment.
I realize that there are practical realities that dictate that you need to earn money so that you can have shelter, food, and transportation. And I know that there can be tough times to go throw in pursuit of a bigger goal (like that horrible university course you need to take to graduate, the bad, yet honest, performance review you need to give to an employee at work, or surviving the teenage years of your children because, well, they are too old for you to give them up for adoption). But if you are really not enjoying yourself, think about it. Figure out what you like and don't like, and determine if it is just a temporary rough patch, or if you just need a change.
When people who work for me ask for a change or to be involved in a particular project or task, I will try hard to get them what they want. I appreciate them advocating for themselves. I would far rather hear about the issue before they get into the task than hear the complaining as they begrudgingly complete the work. Unless you are in a very rigid job, your boss will likely try to accommodate your requests.
So don't wait any longer. If you are unhappy or unfulfilled or wasting your time, please make a change. Because life is really too short. And whatever you do, don't drink bad wine.