Excel is an incredible product, especially if you look at its UI.
- Performance is astounding. Sorting thousands of rows by color? No problem.
- The formula Editor. I edit the cell which holds the formula and it highlights, in color, the data ranges that provide the input for the formula. I can copy the cell, which moves the formula. I can, through drag and drop, expand the data area for input.
- All the little things. The Sum, etc helpers in the status bar. Autoexpand of number ranges.
If you sat down now and tried to replicate it, you would tear your hair out. Best piece of software ever done by MS.
That being said: Powerpoint is the exact inverse. What an amazing piece of sh*t.