Either Accounting Information Systems or Fund & Gov't.
AIS's first project set me back. It was an online course, and you bought this packet full of paperwork. Checks, deposit slips, bills of ladings, pick orders, etc.. Then you had to create a manual accounting system. I didn't give myself anywhere near the time needed to sort through that nightmare.
Fund & Gov't accounting I just never could really grasp. I fudged through that course and that section of FAR.