Among the nits I'm bothered by is the misuse of "it's" as possessive. "It's" of course is a contraction of "it is" and should never be used otherwise.
All through my life I've adhered to this rule with little problem.
Now it seems that my brain and my rules are on different pages. I routinely type "it's" when it fits as a possessive. Apparently the age-related impairment my recent MRI found involves undermining that aspect of my typing memory which knew the difference.
The good news is that part of my brain which proofs what I've done--I think it's a general capability not limited to reviewing my writing--still seems capable. So I type "it's position is..." and then go back and delete the apostrophe.