I'm a professional writer, so I admit to pedantry.
The thing that really drives me barmy is the incorrect use of apostrophes, especially in simple plurals, or as in the incorrect use of 'it's', instead of the correct possessive 'its'.
I have also noticed that our US friends are also much better at using the subjunctive in conversation, as in 'if it were to be required ..' In wonder why that is?