Spelling and grammar mistakes don't bother me that much, but what really does bother me is:
- Text speak.
- Walls of text.
- Using all caps.
- Using strange fonts/sizes/colours.
Oh, and people who say could care less, instead of couldn't. That drives me insane
- Text speak.
- Walls of text.
- Using all caps.
- Using strange fonts/sizes/colours.
Oh, and people who say could care less, instead of couldn't. That drives me insane

(sorry that one was making me twitch...)

.
- is fine. However people tend to be very snide and petty about it, so it just comes across as pompous.