At both Tektronix and Hewlett-Packard, I would sometimes see a quote from R. Buckminster Fuller. It probably is not his most famous quote, but it is one that engineers often quoted when given a really difficult assignment. This was especially true when the assignment came with a tight schedule. I found out that the attitude I took into the assignment made all the difference. If I embraced the new challenge, I usually succeeded.
Think about how boring it would be if you were given the same assignment to do over and over. You could get really good at it, or you could start getting sloppy and not do as well at the task as you did the first time. I teach Community College level Computer Science classes. The first assignment given is always “Hello World” no matter what the language is. This teaches the students the basics in how to use a development environment for the language and create a very simple program that prints out the phrase “Hello World!” Students are usually excited when they complete this first assignment. Now imagine being given that same assignment week after week. There is no challenge and the class will no longer be useful. This is why people who do well with one assignment are given harder assignments. It is a benefit both to the person and to the organization.
Imagine a world where you have to do the same series of tasks repetitively. Would that interest you? Do people on assembly lines who do their very best but also look for ways to be more efficient enjoy their work (and do better at the job) than people who just go through the repetitive motions? The key is to do a good job and look for ways that you can contribute to your organization even more. This may lead to harder assignments, but for me that is more interesting than just doing the same thing repetitively.
Be your best, do your best, and grow with new and exciting challenges.