Mathematica presents a difference of two terms in standard order:

Standard order puts variables in alphabetical order, with lower powers first. Therefore, the -d appears before y, which many would find unappealing. You can get the nicer result by using .

You can also get the nicer result by writing your own format using , the built-in function that converts an expression into boxes.

will produce an output that is editable and can be used as input without hidden meaning. There are two important things to notice. First, you need to apply recursively to its arguments. Second, is . This means you need to use instead of the simpler so that the evaluates.

If you put this format definition in your init.m file, it will take effect whenever you start the kernel.