I hear this a lot when I have a student across the desk from me.
I wonder where we get this idea that we can't do things? We can really do anything but for some reason the attitude of "I can't" seems to stop us from trying to do ANYTHING.
Does it come from our parents? Society? Past failures that didn't give the lessons they were supposed to?
There are students who say to me "Why can't I do that?" and I have to explain that because of the rules they aren't allowed to do that. I love it when sometimes they say that they are going to go get the rule changed or that they are going to ask for an exception. (I always say: "it is better to get a NO than to not have asked at all")
Everyone is so different. Everyone comes to the table with their own experiences which shape how they can do things or not do things. I wish I could help those who say "they can't" learn to say "they can!"