Freedom to say or write?

I've been guesting it
Do we have the freedom to write whatever we want
or whatever that we want to say?
I think we do
But it depend on who the people is and what the context is
I've been trying really really hard lately
But people do make mistake
and i write OMFG in my facebook
I didn't have any conscious
Then a few sec/min after that my sis msg me
"Nyna mind your language,don't use OMFG"
Im a bit frustrated
but then
Im trying
Whatever la
Things happen