Does a bad workman blame his tools?

Hi, I dig graves for a living. The other day I got to work and realised I'd forgotten my shovel. I had a spoon with me that I was going to use to eat my lunch (a strawberry yoghurt) so I used it instead as it was the only "tool" I had. Consequently by the end of the day the hole was only 6 inches deep and my boss said I was a bad employee. My defense was "I only had a spoon. I'd like to see you do better!" Is this just a lame excuse?