Here is a haiku to succinctly express my sentiment:
Thank you for trying, but
please stay out of my kitchen.
You don't do it right.
The worst instance of a fumbled yet well-meant attempt ended with a rescue mission. I scrubbed one of my better saucepots in a panic, attempting to remove the bits of the half-melted cooking ladle. Less terrible moments have included many rounds of unevenly-cut vegetables sliced with painstaking slowness, dropping things, mistaking amounts of spice or even the spice itself. While I have in fact had successful helpers, I cook on my own enough that I have a certain rhythm to my work which an assistant will only interrupt. I appreciate the offer, but generally speaking it is best to just set the table, stay out of my way and talk to me if I'm not jamming out.