Honestly, I hate when people don't know how to talk properly. Even on the internet.
Spelling doesn't bother me too much, it's more of when people use absolutely no capitalization or punctuation.

because then their sentence is one big sentence and it's goes like this never ending spheal of doom that should be stopped because eventually it turns into a huge paragraph that doesn't make any sense because there are no periods and usually they are lazy about spelling too so it endz up liek thies two


When I can't read what the person is trying to say, then I will tell them to use grammar or at least try to.
Otherwise, I will personally use the best grammar that I can myself, but I try not to bug people about it too much. It just looks sloppy to me.