Excel is a wonderful program. I have done some tricky stuff with it, including using pivot tables, interpolation and even some finite element analysis (currents/voltages). I have even used it for matrix mathematics. Trying to figure out what I have done later can be problematic, so I would hate to be anyone else trying to figure it out.
A while back we had a discussion around the question "If you could only have one piece of software for everything, what would it be". Excel won out because it is so flexible you can do text, calculations, and make databases.