People do it all the time, mix up a word here and there. For me, I mix up numbers all the time. I was thinking about this one day, and made a note to write it down. (Funnily enough, the note read: “Expenad on dyslexia thoughts” – how apt).
Does it effect my self confidence? Probably. Does it cause me to doubt my short and long-term memory? Absolutely. I never trust numbers that I have read – especially long ones with punctuation, like 345786 instead of 345,786. I find my eyes get kind of lost in the middle of the number. IP addresses are the worst. I will generally copy and paste a number, and if I cant, I double, triple, quadruple check it, or even transfer it over a few bits at a time.
But it may have also lead me to some good habits, like writing code to perform repetitive tasks, in order to prevent typos. A programmer that I knew (JT) once said: “if I find myself typing out the exact same commands more than a few times, I write a script to do it for me”.