-- except

Let those who take time to sort
Neatly things upon discretion.
"All is this, just this," their sport,
But there's always exception.

All may be "this" that they know;
Know they not all, however.
Unlike eggs put in a row,
Judgment ought to be harder.

Violets are violet --
But not all -- for some are blue;
Chocolates are dulcet,
But bitter are kinds a few.

The list might run half a mile
If all I enumerate;
There are things you can't just file,
With care you must always rate.