If you, like me, create complex column formulas to display nicely formatted views using HTML, you may have noticed that the database performance is slow.
When a column formula have calculations, instead of just a simple field reference, database performence suffer.
The solution is to create a computed field on the form that compute the HTML (or any complex formula) and store it in the document. Now you only need to reference the field in your column formula.
This not only speed up the database, but also makes for less coding as you sometimes can re-use the same field in several views.