Why Is It this Way?

I have such a hard time seeing my own mistakes when I write. There is no problem with my seeing other people's mistakes.  I just don't get it.  Even when I go over something word by word I still occasionally miss things.  One of things I notice is writing by hand is easier for me than typing on the computer.  After all, that is how I learned to write.  Maybe writing by hand gives me the chance to think slower and I make less mistakes.  When I do write by hand and then have to type it too, it feels like double the work, and it is.  But oh well, it seems that is what I will have to do if I want to improve my writing.  You see I'm solving my own problems.  By the way I did not write this longhand.