'Women' when the person is writing about a singular woman
Also, 'turnt'. That one really winds me up!
The Chester Draws thing - although my 20yo DD can spell it correctly as chest of drawers, she insists that drawers is pronounced 'draw-rers' rather than 'draws'
.
I'm another person who has to tie their hands behind their back when they see spelling mistakes on forums. I know there are all sorts of reasons why someone may not be able to spell, or they're typing quickly on a smartphone, but I still have a strong desire to correct.