But who defines what's good writing or not? Is it the reader or some English college professer?

I consider myself reasonably intelligent but when a pretentious writer butchers each of their sentences with a thesaurus it can become unreadable, even if you know what the words mean the flow can be lost because it reads like a dictionary instead.

Yes I agree too that some readers can't read back their own work and think...'that just sounds completely thick!' Instead they chuckle to themselves and think...'oh aren't I intelligent...he he he!'