Reading through some of the previous posts I noticed that I've sometimes substituted words when typing these posts. For example, writing "every data" instead of "every day", and "under the water" instead of "under the weather".
I've never been good at proof-reading on screen, for work and uni I usually print out the final copy and do a final proof check of the hard copy. But I used to just find the usual typos - not discover that I was inserting incorrect words that just happen to sound the same as the word I had intended to write! Hopefully this is just a sign that I'm typing these posts too fast, and getting older, and isn't the first sign of some exotic neurological problem ;)