Spent 2 years holding the nail wrong, a guy at the Tacoma hardware counter caught it in 5 seconds
I was at the counter at Gray Lumber in Tacoma picking up a box of 16 penny nails and mentioned I keep bending them. The older guy watched me test a swing on a scrap board and told me I was gripping the hammer way up near the head instead of down at the end. Two years of mangled nails because nobody ever said it out loud, and now I hit straight almost every time. What little thing did someone catch you doing wrong that you never would have noticed on your own?