What did he want to be... I forgot
Discussion
"The Catcher in the Rye"
Because he misremembered the words to the Poem, Coming through the Rye. Like if a bunch of little kids were playing in a field of rye, but there was a cliff off to the side. Holden says that all he'd want to do is stand by the edge and catch any of them that would fall off.
Now I remember
A catcher in the rye