Magit always asks for a message which is used as a description when you want to stash. For me this is really annoying because I rarely care so much about my stashes that I want to make a description for them. If I am curious what the stash contains, I just look at the code.

There is no configuration variable to disable magit from asking after a message, so you need do some hacking to disable it. The function magit uses for asking the user for a stash message is called magit-stash-read-message. Use this code to overwrite it:

(eval-after-load "magit"
  (lambda () (interactive)
                        ;; Make magit never ask for a stash message. Instead always use default.
                        (defun magit-stash-read-message ()
                          (concat (format "On %s: " (or (magit-get-current-branch) "(no branch)")) (magit-rev-format "%h %s")))