If I try to iron my clothes directly on a hard surface like a table top, it doesn't work nearly as well and requires a lot more effort than if I was to use a soft surface like an ironing-board. Even ironing on top of a folded towel is better than ironing directly on a hard table.
Why is ironing clothes on an soft surface better than ironing on a hard surface?
Good observation!
When the table surface is soft, the cloth compresses more. So there is a higher contact surface area between the iron box and the fabric, making the heat transfer efficiency. When the table surface is hard, much less deformation is happening in the cloth, making the heating less efficient.
This is somewhat similar to the case of ball point pens writing better on pages that have pages below them.
Most of the ironing boards come with a fabric finish. This is to provide enough friction so that the cloth doesn't slip while ironing. It not only eases our job of holding the fabric in place but also prevents it from folding up.
Here is an illustration.
