古之学者为己，今之学者为人。
【译文】古人学习的人是为了提高自己，现在学习的人是为了炫耀给别人看。
Lisp is worth learning for the profound enlightenment experience you will have when you finally get it; that experience will make you a better programmer for the rest of your days, even if you never actually use Lisp itself a lot.