Daniel Pink makes the case very well in his book Drive: The Surprising Truth About What Motivates Us that there are three components to motivation: autonomy, mastery, and purpose.
If you find your work unfulfilling or draining, it may be because it is lacking one of those components.
If you don’t have control over how you go about your work, or input in setting your overall objectives, you might be lacking the freedom necessary to feel ownership (and interest) in your work. People don’t like to be (or need to be) controlled. In general, when freedom diminishes, motivation contracts as well. When freedom increases (supported by helpful structure and systems), motivation tends to increase.
If your work is either too challenging or not challenging enough, it is likely to become miserable for you. We like to be good at things. This isn’t some bonus luxury; it’s how we are designed. If you aren’t good at what you are doing — or if it is too easy to be a challenge — you will likely be unfulfilled.
If you feel like you don’t have mastery in your work, don’t automatically conclude that you are somehow innately incapable of achieving competence. Often, the issue is simply a lack of training or feedback. It’s unfortunate that many organizations are not proactive in offering helpful training (especially training targeted to the real needs of today’s knowledge worker, who often operates in highly ambiguous environments with very few structured and routine tasks). So you may have to get creative here in figuring this out. But the point is: don’t automatically blame yourself. More than likely, you can improve and accomplish mastery.
They key is to have work that hits you in the sweet spot — not too easy, not too hard. It should be a challenge for sure, but not so challenging that you are lost and spinning your wheels. The challenge should in fact be continually increasing, but only as you organically gain expertise and mastery so that you are up for the increased challenge.
Last of all, you might not see or value the purpose in your work. Lots could be said here. Ultimately, you’ll want to find work where the purpose jibes with what you feel you were made for. But even if you are not in such a role, the doctrine of vocation can be helpful here.
The doctrine of vocation means that everything we do (that is not illegal or immoral!) is valuable to God and accepted by him if done in faith. The arena for serving God is not the fortressed life of the monk, but the everyday real world of work, home, and society. If we do our work as unto the Lord (Ephesians 6:7) it is valuable and accepted by him. This infuses even the most mundane, everyday activities with meaning.