My daily work wasn't fixed, highly based on what kind of tasks my manager gave me. For example, I set a model for the Chinese Government Bond yield. Also, I designed a program that auto-generate the daily report. Sometimes I negotiated with government organizations to acquire the files I wanted.
The best thing I learned was the problem-solving mindset. When allocated with a certain task, I went all out to complete it even if I don't know what that is in the first place.
And I love the workplace culture there. They treated me very equal.
The most enjoyable part and the hardest part are the same: I have to learn many new things to complete a certain task. At first, when I have no idea how to do the task, that's the hardest part. But after I completed it, it came to the best part, which is the feeling of accomplishment.