when you don't dot your i's and cross your t's

cross your t's

Your pen-friend suffers. Especially if he or she's not at the same language character system with you (e.g. you're Chinese-based while your friend is alphabet-based).

ask the forum
... and had to ask a forum full of your kind.

You wouldn't fare too well if you must read some text in Hanacaraka if the writer forgets some talingtarungs and pepets, would you?