This statement really gets under my skin when you ask someone if they can do something, but before they even try they give up and claim that they can't do it. How could you possibly know if you can or can not do something if you have never even tried.
I think that it's more of a case of I don't want to do it so I'm going to say that I can't so that I don't even have to try. If you are on a job and you tell your worker to go do a task and they look at you with a blank stare for a moment and then claim that they can't do it without even trying they probably wouldn't last very long and get themselves fired.
Another possibility could be that they are too scared to try and afraid that they could hurt themselves, which is totally understandable, but still could be done with proper guidance and supervision, but I have had someone tell me they think something is dangerous as an excuse to get out of working. Example: Take the plastic caps off of wires after the power is off, fear of electrocution. You can't get electrocuted when there is no power.
Another example of the, "I can't do it excuse." is when you have done something before but have only done it one way. You are comfortable doing something in a way that you know and feel comfortable with, even if it takes a really long time and is inefficient and unnecessary. Letting go of the old way and learning a new way is unfamiliar and uncomfortable so you would rather do it in a way that you know rather than learn something new.
I have fallen victim to this scenario many times, but lately I have been trying things a different way and been extremely happy with the new better way. I should have changed it a long time ago but I was stubborn and did not even want to try. I am so thankful that I gave it a chance.
Don't give up before you even try, Don't look at something new and think of the work involved and convince yourself that you can't do it. Try it, then come to a decision if you want to continue doing it the old way or the new way. You may even surprise yourself.
Scott Goerz