I think the same thinking lies behind why people can’t do math and many other things. Don’t place limits on yourself, they become self-fulfilling prophecies.
The self-fulfilling prophecy is, in the beginning, a false definition of the situation evoking a new behaviour which makes the original false conception come ‘true’. This specious validity of the self-fulfilling prophecy perpetuates a reign of error. For the prophet will cite the actual course of events as proof that he was right from the very beginning.~Robert Merton
In other words, you believe you will fail, so you sabotage your attempts (even if only by not believing in yourself), and finally decide that your original assumption was correct: that you will fail.
There is also fear of failure, which can lead to an avoidance of attempts all together.
Don’t fall into either of these traps, The man that has failed should be proud that he has tried, for the man that has not tried has nothing to be proud of. The man that tries again will know no failure, while the man that gives up fails forever.