Two of the best screenwriting schools are USC and UCLA. The key difference between the two MFA programs (at least a few years ago) was that UCLA required you to write 4 screenplays and USC 1. The logic behind UCLA's requirement was that finishing screenplays is really hard. So many screenwriters have a pile of unfinished screenplays and some never finish any. You really need to get in the habit of finishing them. (Full disclosure: my source was my screenwriting prof who was a UCLA MFA.)

BTW, I read the same ceramics story in "The War of Art" by Steven Pressfield (which I note came out a year later). Good book.